Vista - new computer, sporadic internet

Hi all,

Just got a new computer from dell with vista home premium 32 bit sp1, and internet is not working well. It does work, but will work great anywhere from 10-30 seconds, before it seems to completely stop working for 10-60 seconds. Its a constant loop and doesn't work permanently for more than a minute at all. I believe the ISP is fine because it works great on games and using the internet on the ps3 or 360, just cuts out sporadically on the computer.

I believe I had this problem before too, when I got my laptop 2 years ago, but forgot what I did to solve it.

I have cable internet directly into my computer, no router. Comcast already came out and said they fixed it, but left before it stopped working again, leaving immediately after tweaking some settings. resetting the modem or computer doesn't help, the sporadic internet cyle is constant, with no periods of long connectivity.

Any help would be appreciated, and I can post more info if anyone needs it.