Windows 7 Ultimate & Router issue

Hello all.
Seems to be alot of these issues. After looking around i have yet to see an issue like mine so i figured i would ask.

Ok here goes. Im running W7 Ultimate edition my router & wireless network is running off a linksys WRT160N with Firmware Version: v3.0.00.

My internet provider is comcast high speed.

Fresh format and install of W7 from XP Pro with no issues

My problem is the longer my PC is running my bandwith bogs down.

Example: speakeasy.com speed test
Download Speed: 27468 kbps (3433.5 KB/sec transfer rate)
Upload Speed: 8650 kbps (1081.3 KB/sec transfer rate)

mmmmm pretty fast.
now after my PC is running for about 2 hours or so even when not downloading or doing anything it bogs down almost half what i should have for bandwith. more then 2 hours it gets worse and worse to the point were after many hours it becomes a hassle to even open a web page let alone download anything.

Ive totally reset my router & cable modem ( which as you all know is a real pain to set your wireless network back up ) and it was fine again. After a few hours ... it starts again.

The only easy way i found to temp. fix this is to unplug my router for a few sec and plug it back in and poof my bandwith is back ( atleast for a few hours till it starts bogging down again )

Anyone have any idea's? Ive tried a few tips from this site like running cmd and ipconfig/flushdns but i dont think that helped.

Any help offered would be great. If anyone needs anymore info about my network and pc spec's let me know and thanks in advance all.

seems to have done the trick for now. firmware upgraded to 3.02
i shall report status in a few hours with my fingers crossed