I took my PC to my friends for a LAN and when I came back, the computer wont connect to the internet ... the problem can't be with the network because of the fact that I am on my parents business comp 2 rooms away from the PC that isn't working. I tried running ipconfig to try pinging, but when I type in ipconfig in the run window, it comes up and disappears in less than a second. Any advice?

edit: Also, I have tried running Renew IP in the network manager or whatever and it can't renew the IP.

I resolved my proplem with ipconfig by doing the following :
(As this is usually a result of firewall protection)
I checked my norton security settings and went to the options menu
Then the firewall tab
Advanced security settings
Uncheck stealth blocked ports
Clicked okay
This should resolve the issue if you are using Norton Security
Other firewall protection products will vary.

Norton - the curse of the computing world - get rid of it - especially if on a network, will cause you nothing but trouble, as well as slow your PC down to an absolute crawl

What software do you recommend for security and anti-virus?