How to stop my computer from freezing constantly?

my comp keeps frezsing I get 20 min on it and it freezes so I restart and get like 5 to 10 more min. what can I do I just added new hard ware I also have no anti virus is there a way I can check to see if I have a virus without downloading anything does xp have a virus scan on it? my comp was fine I put a bunch of new hard ware on it it was fine the 2 days ago I put in a new sound card it was fine then about 2 hours after the sond card went in it has been doing this what can I do and where can I download a virus protection program fee legally no demos

My computer does the same. I just let it sit, when it freezes, for like 10 minutes. It usually will start working again. It is just having problems processing programs.

same

 
HouseCall is a free online virus scanner offered by Trend Micro, which checks whether a computer has been infected by viruses, spyware, or other malware.

http://housecall.tre...
 
 
Eusing Free Registry Cleaner is good and relatively fast.

http://www.eusing.co...

 
Ad-aware removes spyware and it's FREE!

http://www.lavasoftu...

Go to above link and Download

 
If you don't have an Anti-Virus program on your computer, consider getting AVG. It has a FREE edition for non-commercial use. I've used it for years and am well satisfied.

http://free.grisoft....

it might not be a virus if your computer is having trouble accessing information and freezing you might need to defragment your drive to organize your files for quicker access or it could be a sign that your hard drive is getting ready to die but its unlikely that a virus would cause it to freeze for a just 10 minutes so either put more memory in your computer so it doesnt get bogged down looking for information or try a new hard drive with a faster rpm 10000rpm and a 2.5 inch drive is one of the fastest ones right now