New build timing out

[xpavement]

Here is my new build:

XFX 650i Ultra (P03 BIOS)
Core2Duo E6850 (@stock speed)
2gig OCZ DDR2-667
Geforce 8500GT
320 Seagate SATA HD
Lite-On SATA DVD-RW
HEC Orion 585 watt power
Windows XP w/SP2 (with dual core hotfixes installed)

Everything went smooth with the build and installing windows XP, but my internet connection tends to timeout when connecting to any websites soon after windows loads. The connection goes in and out, sometimes working, sometimes not. It's almost if I wait five minutes after getting into windows, I can start browsing sites without any problems, until I reboot. I can even mount a local samba share on my file server as soon as I boot and stream audio and video to it without any hiccups, but at the same time, my connection to websites continually times out. It is very strange.

I've tried changing cables, using a different slot on my switch, reinstalling XP, but nothing has improved matters. What is even more strange is I loaded up an Ubuntu live cd, and I immediately could surf the web without any delays or timeouts. I did not install the nvidia firewall or NAM software either. The other systems on my network, work fine, so don't think it's router/connection issue either (I'm going to test a backup router just in case). I've tried messing with the hardware settings on the device manager, such as "Speed/Duplex Settings" & Optimize For", and no adjustment has made a difference.

Any ideas on things to try?

 

[xpavement]

Thanks for all those that looked at my post, this seems to have been a router issue, as I tested a backup router, and non of the same issues occurred, so I'll stick with the *new* router for now.