I had another big frustration today. Unfortunately I reformated one computer before I found the fix, but it saved me a lot of time on the next computer that had the same problem.
Some Windows XP machines with AMD processors get caught in a reset loop after installing Service Pack 3. After running this little command, the problem goes away.
There are also a few other tips that resolve this problem caused by other issues, surprisingly Norton products can also cause reset loops after installing Service Pack 3.