possible reason for error:
Stop 0x0000007F or UNEXPECTED_KERNEL_MODE_TRAP
The Stop 0x7F message indicates that one of three types of problems occurred in kernel-mode:
Resolving the Problem:
A condition that the kernel is not allowed to have or intercept (also known as a bound trap).
Stop 0x7F messages are typically due to defective, malfunctioning, or failed memory hardware. If you added new hardware recently, remove and replace it to determine if it is causing or contributing to the problem. Run diagnostics software supplied by the system manufacturer to determine if the component has failed.
Running the CPU beyond the rated specification, known as "overclocking," can cause Stop 0x7F or other error messages due to heat buildup. When diagnosing problems on overclocked systems, first restore all clock and bus speed settings to the manufacturer recommended values to determine if this resolves the issues.
The problem might also be due to cracks, scratched traces, or defective components on the motherboard. If all else fails, take the system motherboard to a repair facility for diagnostic testing.
Stop 0x7F messages can occur after installing incompatible applications, drivers, or system services. Contact the software manufacturer about possible Windows XP Professional-specific updates. Using updated software is especially important for backup programs, multimedia applications, antivirus scanners, and CD mastering tools.
Your Windows 2000-based computer or Windows XP-based computer that is running Terminal Services may stop responding, and then you receive the following error message on a blue screen:
0x0000007f (0x00000008) error STOP 0x7f
The Win32k.sys file is listed as the source of the Stop error.
When you shut down and restart your computer, the computer starts normally. However, the Stop error recurs regularly.
Error Message: "STOP 0x0000007F" During Setup on HP Pavilion 7840
When you try to install or upgrade to Microsoft Windows XP Professional or Microsoft Windows XP Home Edition on a Hewlett Packard Pavilion 7840 computer, you may notice the following behavior. The first time that you restart the computer, you may receive the following error message: STOP 0x0000007F (UNEXPECTED_KERNEL_MODE_TRAP)
Computer Turns Off During Text-Mode Setup If it Is Too Hot
When performing a clean installation of Windows XP, you may experience one of the following symptoms during the text-mode portion of Setup: You may receive a "STOP 0x0000007F" error message. The Welcome screen may appear, and your computer may then turn off.
0x0000007F or UNEXPECTED_KERNEL_MODE_TRAP (TechNet article)
The Stop 0x7F message indicates that one of three types of problems occurred in kernel-mode: A condition that the kernel is not allowed to have or intercept (also known as a bound trap); Software problems; Hardware failures.