“This operation has been cancelled due to restrictions if effect on this computer. Please contact your system administrator.”

This problem is generally caused by a corrupt Internet Explorer registry key. As such, the first thing you should try is resetting web settings in Internet Explorer. In Internet Exploer, click the Tools menu, click and select Internet Options. In Windows XP, go to the Programs tab, and then click the Reset button. In Windows Vista and Windows 7, click the Advanced tab then select reset. Apply the changes.

If that doesn’t work, you will need to edit the registry, following these steps, as described by Slipstick Systems:

1. Start, click Run, type Regedit in the Open box, and then click OK.
2. Browse to HKEY_CURRENT_USER\Software\Classes\.html
3. Right click the value for the .html key and select Modify…
4. Change the value from “ChromeHTML” to “htmlfile” (or from FireFoxHTML to htmlfile)

Repeat this process for each of the following keys:

• [HKEY_CURRENT_USER\Software\Classes\.htm]
• [HKEY_CURRENT_USER\Software\Classes\.html]
• [HKEY_CURRENT_USER\Software\Classes\.shtml]
• [HKEY_CURRENT_USER\Software\Classes\.xht]
• [HKEY_CURRENT_USER\Software\Classes\.xhtml]

Fixes

Change network setting to home or work If you have your group set to “Public” in the Network and Sharing Center in Windows Vista SP2, the system will be undiscovrable by Windows XP machines on the network. Open your Control Panel, then select Network and Sharing Center, and change the setting to either “Work” or “Home.” Make sure that all computers are using the same group.

Make sure Network Discovery is turned on In Windows Vista, go back to the Network and Sharing Center in the Control Panel, and make sure that the “Network Discovery” option is set to “On.”

You may need to restart your computer after applying these changes.

Here are a few tips that can dramatically increase the speed of a slow Firefox 3.5:

Change maximum number of requests If you’re using a broadband connection, chances are that you can speed up Firefox by allowing it to perform multiple simultaneous requests to Web pages instead of performing one request at a time. To do this, type about:config in the URL bar (where you would normally enter a Web address) then look for the following entries, and make these changes:

• network.http.pipelining – set this to “true”
• network.http.proxy.pipelining – set this to “true”
• network.http.pipelining.maxrequests – set the integer value to 20
• network.dns.disableIPv6 – set this to “false”

Quit then re-launch Firefox after making these changes.

Reduce history Having tons of items stored in history can slow down Firefox’s launch and operation speed significantly. Navigate to Tools > Options, then click on the “Privacy” tab. The default setting is 90 days. Reducing this number to 5 or 10 days can result in a substantial performance boost.

Remove extensions and themes then re-add them, one by one Some extensions and/or themes may conflict with Firefox 3.5 or cause performance issues. You can isolate the problematic items and eliminate them permanently by uninstalling all of them then adding them back one by one to identify the culprit(s). Follow these steps, as published on MozillaZine.

1. Click Tools > Add-ons
2. Click on the Extensions or Themes button on the top
3. Click on the extension or theme you want to uninstall
4. Click Uninstall
5. Restart Firefox

In fact, just reducing the number of extensions or themes installed can have a beneficial effect on speed.

• “Windows Explorer has encountered a problem and needs to close”

The first thing you need to do, if this problem occurs as soon as your system starts up or whenever you click on any file or try to perform any other action, is download a copy of Universal Explorer, an alternative file viewer. This will at least allow you access to the system so that you can make changes and begin troubleshooting.

Next, begin with the following potential fixes:

Turn off DEP In some cases, Data Execution Prevention may be causing the crashes to occur. Turning this option off for Windows Explorer may leave your system more vulnerable to viruses and other malware, but may allow your system to function properly until you can find another workaround. To turn off DEP for Windows Explorer, follow these steps:

1. Click the Start button
2. Open the Control Panel
3. Open System
4. Select the “Advanced” tab
5. Under “Performance,” choose Settings.
6. Select the “Data Execution Prevention” tab.
7. Select the option “Turn on DEP for all programs and services except those I select.”
8. Click “Add…”
9. Find Windows Explorer, which is generally located in c:\windows\explorer.exe and select it.
10. Restart your system and check for persistence of the issue

Note that if Windows Explorer keeps crashing during the above steps, you can open the command line and type bcdedit.exe /set {current} nx AlwaysOff and accomplish the same effect.

Disable Shell extensions The site HelpWithWindows suggests that errant shell extensions may be to blame for Windows Explorer crashes, especially in cases wherein the issue occurs upon right-clicking certain files.

Download and install the tool ShellExView. It will show the description, as well as version details, company information, location, file name and more of any installed shell extensions and allow you to disable them.

Start by disabling all third-party shell extensions, then restarting your computer. If Windows Explorer doesn’t continue crashing, you know that a shell extension is to blame. Start re-enabling them one-by-one or in groups until you identify the culprit, then leave it disabled.

Switch antivirus software As we have noted, the presence of two overlapping antivirus or antimalware/spyware/firewall tools can cause various conflicts. Users should install one (and only one) strong anti-virus package and make sure it’s up-to-date.

In addition, certain antivirus packages can conflict with installed system software while other antivirus packages are not.

If you have already tried the aforementioned workarounds, completely remove or disable all antivirus/spyware software (Norton 360, ZoneAlarm, AVG, etc.). In fact, you may need to uninstall the packages–simply disabling may not work.

Next, re-install one and only one solid antivirus/spyware tool. If the crashes still occur, uninstall that package and try a different one.

Fixes

Try compatibility mode In the IE 8 toolbar, click on the small icon that looks like a page broken in half, next to the refresh button (pictured below). This invokes “Compatibility View,” which can fix the Netflix issue.

Source: Microsoft

If the issue persists and you would like to downgrade to Internet Explorer 7, follow the instructions in this Microsoft Knowledge Base article.

Use the beta Netflix player The Netflix beta player, which is based on Silverlight, works better under Windows 7 for a number of users.

Fix

In some cases this issue can be resolved by recreating your iTunes media library. This can be accomplished via the following process:

1. Quit iTunes if it is open
2. Navigate to the following directory: \Documents and
   Settings\username\My Documents\My Music\
3. Open the iTunes folder
4. Remove the following files: iTunes Music Library.xml and iTunes Library.itl. Put them in another location on your hard drive for safe-keeping.
5. Launch iTunes and navigate to the "File" menu then select "Import." Find the file iTunes Music Library.xml from the previous step and click "Choose."
6. Failing the above, quit iTunes and navigate to \Documents and Settings\username\My Documents\My Music\ and delete all files in the "iTunes" folder. Next, launch iTunes again and re-select "Import" from the "File" menu. Locate and re-import all of your music and other media.

Fix

This problem can generally be easily fixed by copying the Adobe PDF plug-in to the Google Chrome Plugins folder. You may need to create the Plugins folder yourself if one does not already exist. Follow these steps:

1. Go to Program Files\Adobe\Acrobat(version number)\Acrobat\Browser
2. Copy the file nppdf32.dll
3. If you are using Windows XP, go to C:\Documents and Settings\(username)\Local Settings\Application Data\Google\Chrome\Application\(Version Number)\. If there is not a Plugins folder there, create a new folder with the name “Plugins.” Paste nppdf32.dll into the Plugins folder. Quit and restart Google Chrome and retry PDF access.
4. If you are using Windows Vista or Windows 7, go to (username)\AppData\Local\Google\Chrome\Application\. If there is not a Plugins folder there, create a new folder with the name “Plugins.” Paste nppdf32.dll into the Plugins folder. Quit and restart Google Chrome and retry PDF access.

Failing the above, use an alternative reader. One good choice is the free Foxit Reader. It tends to use fewer resources than Adobe Reader, and works well in Windows 7.

Kill IEUSER.EXE task Launch the task manager by pressing control-alt-delete, then launch Internet Explorer. Immediately after the browser launches, end the process “IEUSER.EXE” in Task Manager.

Turn off protected mode While this shouldn’t be your first course of action, as it could create serious vulnerabilties and open your system up to attack, several users have reported that turning off Internet Explorer’s protect mode resolves persistent crashes. To do so, click the Security tab, select a Web content zone, and then change the “Enable Protected Mode” check box to disabled for the desired items.

The tool’s documentation states its “report will let you know if your PC meets the system requirements, if there are any known compatibility issues with your programs and devices, and will also provide guidance on your upgrade options to Windows 7.”

Upgrade Advisor can run under Windows 7, Windows Vista or Windows XP Service Pack 2. It is available for download from Microsoft’s download center.

Fixes

Change network setting to home or work If you have your group set to “Public” in the Network and Sharing Center in Windows 7, the system will be undiscovrable by Windows XP machines on the network. Open your Control Panel, then select Network and Sharing Center, and change the setting to either “Work” or “Home.” Make sure that all computers are using the same group.

Make sure Network Discovery is turned on In Windows 7, go back to the Network and Sharing Center in the Control Panel, and make sure that the “Network Discovery” option is set to “On.”

You may need to restart your computer after applying these changes.