Wireless says connected but drops after seconds of use.

I have a friends laptop who was having trouble connecting to the internet. She has consistently excellent wireless connection, but after just a minute or less the internet stops working. The excellent signal strength never goes away and it says connected, but you can't do anything that requires an internet access. After lots of playing with the problem I even tried to do a fresh install of her Windows XP, but I got an I/O error and even after changing BIOS to boot from CD/DVD I couldn't get the Windows install to go.

I also took the laptop home to my network that works perfectly and have multiple other computers running on it. With the laptop it does the same thing it did on her network.

Any suggestions? :confused: