Internet access frequently lost thru wan connection

I am using a dlink dwl g520 on my computer. I have Windows XP. The problem is that I can use the internet for exactly ten minutes after turning my computer on, then it doesnt work anymore. The connection itself is still there, just access is lost. I have a file sharing program (Bearshare) that continues to work all the time. I have called tech supports and had friends who are good with this sort of thing come over and look at it, and nobody can figure it out. D-link told me to call Microsoft, and Microsoft told me to call D-link. Could someone point me in the right direction?

 

Have you tried upgrading the firmware?

 

Ive already tried reinstalling the modem. The connection isnt lost though, its the access to the internet. I can still use the filesharing program. Ive tried many differnent browsers and they all do the same thing