Router problems-Frequent disconnects

I have a Belkin 4 port cable/dsl gateway router F5D5231-4 that disconnects from the internet very often, 4 or 5 times a day. When it does that I also notice that the network between my two computers is also not working and I cannot even connect to the router via the user interface. The only way to get reconnected is to reboot the router by unplugging it from the power source.

I have two computers connected to this router. Computer #1, which is the main computer that the family uses and Computer #2, which is in a study room for the kids.

One day I was doing some maintenance on #2 and while it was turned off/unplugged from the network I noticed that the network never went down, the router seemed to preform fine when only connected to Computer #1. I left Computer #2 off of the network for several days and during that time the router did not freeze up once.

Now my question is, what is it about computer #2 that I need to check? Obviously there is something about having that computer on the network that is messing up the router.

Both computers are running windows xp pro and have SP2 installed. (the problem is not SP2 related since I have had this problem for months now and just yesterday installed SP2 on both) I have checked the Belkin website to see if there has been any firmware updates but there has not been any since release.

Thanks for any help that you can give.