Try to enter safe mode (reboot then use F8 keystroke), once in safe mode, go into msconfig, and shutdown any hardware that is not a required windows function. Once completed, you will be prompted to restart, just click yes, and once back on your desktop, try opening a program, it could ba a hardware issue. If the condition remains the same, restart the system in DOS from the shutdown menu, then perform the scanreg /fix command string and it should fix the system.dat file causing the issue.