Computer still freezing

My computer freezes constantly. I've run scandisk, virusscan, defrag, adaware. I replaced a fan that wasn't working, I don't know if it was the right kind but it does spin around. I'm pretty sure I need a new video card because I have a weird ghosting affect horizontally from any dark areas on screen. I know this isn't the monitor cause I bought a new one. I got a program that checks the temp of my CPU and case. I don't know what normal temperatures are. Last time it froze the CPU was at 105 farenheit. I let the computer cool off for a few hours and turned it back on just now. It started at 86 Farenheit and it's creeping up now(Which I guess I should expect), in the five minutes it's been on it's up to 91 Farenheit. Could this be my problem, if not any other ideas on what I should do? Here are the computers specs:

Windows XP Professional - Service Pack 2
Intel Pentium 4 1400MHz 1.4GHz
512MB RAM
45 GB Hard Drive

Thanks

 

lol i just read in one of the threads that to check if it is overheating take the side case off and let a big fan blow in it. if it doesnt freeze after that then i guess its overheating.

 

91F is 33C, 105F is sill only 41C, both are cool in terms of processor temp, so i doubt overheating is an issue.

have you tried upgrading the drivers for all hardware? which fan did you replace? may try a repair of xp.