I had a laptop computer with that had the STOP 0x0000007E blue screen error code. It happened while starting Windows, even in safe mode. I knew from the customer told me that he had a malware problem. Since I could even get into Windows, I didn't know what exactly was causing this issue. Every article I've read said it was a driver issue. And I think that is correct considering it happened before Windows even loaded. The two knowledgebase articles (here and here) that I found from Microsoft did not help. Neither did a simple disk check.

I pulled the hard drive out of the laptop and scanned it with an antivirus and antimalware program. There was some very nasty stuff on that computer, even a rootkit. After cleaning up the malware, I put the hard drive back in the computer. Still, the STOP 0x7E message was there.

This meant I had only one option left: the in-place upgrade, commonly known as a repair installation. I find that the in-place upgrade option can fix bad drivers because you are forced to re-install them during the setup process. If the driver is bad, you can simply delete the file before it detects it. Pressing the SHIFT + F10 keys brings up a command prompt which can use to find the bad driver file and delete it. In any event, performing the in-place upgrade fixed the problem.

Not every installation of Windows XP can perform an in-place upgrade. But if it can, it is my experinece that 95 times out 100 it fixes any problem you have with getting Windows to start. It is time consuming, but effective.