Cannot connect to internet through a browser!

Okay, so i one day i tried to get on the internet, but every browser i tried couldn't connect. The browsers i use are IE, Firefox, and Chrome. I can connect to the internet through MSN messenger, Limerwire, and Skype. I have been told to reinstall my OS, but i dont know how to do that and am hoping someone here knows another way to fix this problem. I use Windows XP. If i have to reinstall OS can someone give me a guide for a beginner on how to do that.

run->cmd
then enter
ipconfig /all >mytcp.txt

in your follow-up, attach mytcp.txt

also see this for testing your network config:
http://www.techspot.com/vb/topic55006.html

P2P software is installed. (Limewire)...
This is a likely source of malware.
If you have a virus or other malware infection, P2P software will need to be removed...

Is your AV, Antispy, and Firewall software up-to-date (and properly configured)?
If you have a virus or other malware, you will likely wish to start a new thread in that area...

See this information if you think this may be a possibility.

You need to read, understand, and strictly follow the directions
which you find at the top of virus and malware board.

Start with... http://www.techspot.com/vb/topic120350.html
Then ... http://www.techspot.com/vb/topic58138.html
Followed by ... http://www.techspot.com/vb/topic65943.html

If you find malware / virus infections, you will want to start a new thread there...

Once you have posted the three (3) logs mentioned in the 8 steps,
one of the experienced helpers will be more able to assist you.

How to post your Hijackthis log-file as an ATTACHMENT:
http://www.techspot.com/vb/topic19133.html

Good Luck. Repost if you have difficulties along the way.