[UPDATE: A Microsoft TechNet discussion thread is tracking this issue and has the latest updates on potential fixes, along with commentary from Microsoft indicating that the company is working with system manufacturers to resolve this issue.]
Several users have reported an issue in which a blue screen of death (BSOD) accompanied by the error message “Multiprocessor_Configuration_Not_Supported” appears after attempting to install either Windows Vista SP2 or Windows 7.
This error generally indicates that the system has multiple processors, but they are asymmetric in relation to one another. However, many users are receiving the message on systems with only one processor or systems with only one dual-core processors.
A reliable workaround for this issue has not yet been discovered, but, in some cases, a BIOS update may resolve the problem. Here are instructions for updating the BIOS on Intel motherboards, and here are instructions for other motherboards.