Constant HDD thrashing after cable modem install

[Deckard_BR]

Howdy. I've had a really unusual problem since Saturday morning. Basically, my hard drive thrashes constantly during system launch, program launches and system shut down. My HDD activity light goes solid yellow and stays that way for 3-5 minutes on each occasion, delaying the program launch by an inordinately long period. In short, it's really interfering with system operation. Task Manager shows spikes in CPU usage to 77-99% during these activity periods. My system now takes about 10 minutes to come up.

The one major change that occurred during that time was Comcast coming by to install a replacement cable modem. I had an older RCA model which developed a loose connection, and he replaced it with a Motorola Surfboard 5120. I'm not entirely sure what he did to the network settings on my system, but now, in addition to the LAN 6 connection I had before, I have an open connection called "Internet Gateway" that I'm reasonably sure wasn't there before. I haven't rung up Comcast yet, but that's my next step tonight.

My first thought was virus/spyware, but McAfee and Spybot both swear my system's clean, and the issue's not going anywhere.

Here's the bona fides, in case anyone has any suggestions:

Homebrew system
Intel Pentium4 3.0 GHz w/HT
1 GB RAM (640 MB shows free after all startup programs load)
WinXP Home SP2
80GB HDD (5 GB free)
ATi RADEON 9500 PRO 128MB AGP
SB Audigy2

Is it a network settings conflict, maybe something else?

[rightcoast]

I saw this one yesterday, but thought I would wait to see what comcast has to say. Did you have any luck with them?

[Statica]

The internet gateway is just XP's detection of your modem as a UPnP device. It's not an issue if you are behind a router, which you should consider getting into. How is the modem connected? USB or Ethernet?

[Deckard_BR]

Well, a couple of Comcast guys jawed at me yesterday. I swear, if I put the modem in standby mode (btw, it's an Ethernet hookup), the thrashing problem goes away or lessens. First guy seemed to think it was a problem with the modem itself, since I wasn't getting an internet connection when I talked to him. Power-cycling the modem during a complete system shutdown, however, restored connectivity, and I called them back and talked to a guy who said there couldn't possibly be a connection between one and the other.

I've noticed some spikes in memory or CPU usage, but nothing that appears to coincide directly with the thrashing. One fellow at protonic suggested I run about 3 other spyware detectors in addition to Spybot. The behavior is *very* much like a virus or spyware program, but, given McAfee's and Spybot's inability to detect either, I'm not sure what to think.

I ran a defrag this morning, and I'll run the spyware cleaners tonight. In the meantime, I invite speculation. I'd hate to have to go the System Restore route, but I'll do it if I have to.

P.S., I no longer think the Internet Gateway connection has anything to do with it. That appears to be normal.