just pay attention to where u unpluged the old fan and plug the new one right in the same spot!
also...
make sure you have a good intake and exaust flow to get fresh air in the box. if your just reblowing the same hot air across your HS, its kind of pointless. u need a constant flow of fresh air from the outside.
also...
make sure u have quality thermal paste on your cpu/hs interface. thermal pads are crap! i was running hot a few weeks ago (about 59-60*C on my k7 AMD XP). i bought some Artic Silver 5 off ebay for $7. too my horror, i found some shotty white gunk the guy who built my rig claims to be thermal grease. wiped it off w/ alcohol and put a dab of the AS5 on. **be sure to let the AS5 set in for a day before OCing or anything because it takes time to set in/up** now i run at 48*C without changing anything else! i can also overclock ~.1-.2 GHz with no increase in temp!
it was not the heatsink. I just found out that my video card was overheating causing high temps. Now my card's fried and it looks like someone took a blowtorch to it