i dont know if this is even related to my problem i have now, but lately my desktop(dell dimension 2400) has been slowing down.  I figured it was the ram dying because ive had the bluescreen in the past and it seemed as though it was related to hardware.  but it wasnt REALLY a problem until the last couple of days.
so now i cannot connect to the internet with that computer. it is hooked directly to a linksys router and modem which both WORK FINE, this laptop is connected to the internet wirelessly and it works fine.  i TRIED using comcast's 'desktop doctor' but i got an error message saying : 'the application or DLL C:\\windows\system32\digest.dll is not a valid windows image. please check this against your installation diskette.'
i tried again and now it just SAYS: verifying connectivity...failed!
so i scanned my computer with avg 8.0.234 with database: 270.10.20/1943, and all i found was some tracker cookies, deleted them, no results
then i scanned with spybot s&s
it didnt find anything
then i tried running winsockfix
no results either
i tried turning my firewall off , no results, back on, no results
i tried releasing and renewing my ip -- nothing
and i tried unplugging my router and modem and plugging back in, nothing
under network connections it says that i am connected to my local area network
but all websites opened, along with pings sent out fail

anyone have any ideas?digest.dll, located in C:\\windows\system32 is a valid M$ file

Did you try to connect the desktop straight to the modem, bypassing router?