-HELP- cant connect to internet

ive had my windows vista 64bit computer for about 3 months and virtualy no problems at all. but all of a sudden while on the computer talking on aim a week ago my net drops. happns sumtimes so i just did my usual steps to fix it. none of them worked and thats when i became worried. i called my cable company and they said they saw no problems with my connection and i belived them because oddly my computer said i was connected to the internet but nothing would connect.... and also i have a router that splits off into a wireless connection for a differnt laptop which has having no problems either.

so basicly all in all ive tried all the basics, (ipconfig /release /renew, ipconfig/flushdns, scanned with my nod32 and spybot) and for some reason the desktop comp wont connect. please help me ive never seen anything like this before