Crazy modem crashing problem

For the past few weeks, my cable modem has been acting up so strangely. It has been crashing (all of the lights turn off except power) a lot of the times when I try to access EVE-Online, an online game. When the problem first started, I also got this when trying to access Windows Update. It dosn't do that anymore, so I tried to contact EVE tech support to see what was up, and they were no help.

Further experimenting reveals that it is not solely EVE's fault, but this happens whenever I load things that are resource intensive. I've noticed it when starting the F.E.A.R Demo, Doom 3, and even Prime 95. I think I even noticed this when I woke up to come back to my monitor out of standby. It seems to work just fine all day, I can download large files, chat on AIM or MSN, and access websites fine and dandy.

Some of the things I have tried to correct this problem were, well, to update my entire computer. No change. I got so frustrated that I eventually reformatted and reinstalled! The problem persists. Last night I tried out Microsofts memory testing thing to see if my memory was bad, but after three passes, there were still no errors. I contacted Cox (my ISP) tech support and we were both still stumped. We eventually decided that my modem had probably gone bad, but, after the chat with him, I experimented some more and found out problem exists with applications that do not request net access (like Prime 95 and Doom 3, both of which I had blocked with Sygate Firewall for experimentation purposes. I don't even think Prime 95 requested 'net access.)

I'm in the process of updating my BiOS, but the auto-update utility that is supplied with the instalation CD says the servers are busy, so I must wait.
Since I went as far as reinstalling Windows, I'm doubting it has anything to do with anything software oriented, so I'm concentrating on my hardware, which is as follows:

Asus A8N Deluxe Motherboard
AMD 3000+ Processor
2x 512MB Kingston Memory (not overclocked, like the rest of my system)
1x Geforce 6600 GT
2x 80 gig harddrives, one SATA, one IDE (hope I'm right there about their descriptions, kind of confused in that area). They are both from Western Digital.
Soundblaster Audigy 2 Value
1 Liteon CD/DVD burner and one generic floppy drive.
My powersource is the defult one that came with my case, which is made by Antec and is 380 watts.

I'm running Windows XP Home service pack 1, but all updated otherwise. I tried SP2 before my reformat and it gave me a lot of problems, so I'm not wanting to install it again ('specially since it didn't help any)

I'm completely stumped here. I'm experimenting with the thought that something inside my computer is overheating. Could a hot nForce chip cause something like this? The problem is terribly sporadic.... sometimes it does it, somtimes it dosn't. It's just so confusing.

Congradulations, you've made it all the way through my really long and detailed post! Thanks

 

So have ruled out your modem by running your machine without it installed drivers and all for a few days?