major FPS lose, all of a sudden in Nvidia card

Ok i got my pc like 4 months ago it has a GeForce FX 5200. and i play SoF2, all worked awsome and good, using the 44.03 drivers. and using com_maxfps 85 so i can have steady and constand fps of about 85-90.a week ago my HD crashed, so im waiting on new hd to be delivered but in the mean time i went and bought a western digital 80GB. Installed this new hd on my 2nd pc a P3 600mhz with a Nvidia TNT pro, which i used to play b4 getting the new pc, i did this because i wanted to use win98 but when installed the hd in the new pc, the pc would not accept the hdas it was recovered by a different system recovery cd.

Then i put the new HD in my new pc P4,winxp 2.80ghz 512mb ram, and used its on system recovery cd and the winXP got installed in the 80gb hd. i updated the system, d/l the patch for SoF2, installed the game even used the same drivers 44.03, and the same config as i had backed it up and used the same com_maxfps 85. so then i go to play and my fps is ok 80, then it started getting weird, fps would drop down to like 40-50 and just getting crazy going up, down, up, down and all this when in a fight or in fogy maps or maps that need a lot of power, now i know that the geforce fx 5200 can do much more than 30-50 fps. never had this problem b4 so something is not right here. my only guess would be that the hd was not totally wiped out in the 2nd system recovery and some #### from the nvidia tnt pro r still there and giving me this bs now. but its really annoying lol. anyone got any ideas? #### long post and probly wont even make sense lol.