I had the same problem with a 1.2 T-Bird and win 98. I underclocked my 1.2 when they first came out because it kept overheating. Once there were HS and fam combos that could keep that CPU cool I brought the FSB back to 133. Windows didn't like that at all. I had to reformat and reinstall windows.
Then it was fine. Good luck. Post your results.
Hang in there. It can only get better!