So I have been having some odd computer problems, and thus far have failed to diagnose the exact cause of them. Lets see if any of yall can help me out.

Here are the symptoms:

Symptom A: About every 2 or 3 days I get a message on my computer that reads something like "VPtray.exe has tried to read such-an-such spot in memory had has failed and must close." I then must press okay and allow the program to close. For those of you who are wondering, VPtray.exe is part of the Symantec Antivirus program and is more specifically the little program that is resident in the Windows system tray.

Now, many of you are saying, "So what....some program fails and you have to close it, who cares", but that is not the end of it. Once VPtray fails, everything fails. My computer is literally stopped dead in its tracks. I cannot run a single executable file. All network communication is down. There is no communication over the USB ports (my USB mouse fails to work, but I can still use my laptop touch pad). I can't even press CTRL-ALT-DEL to get some system diagnostics up....it just gives me an error message and fails to open.

In short, every 2 to 3 days when I get this error message about my Symantec Antivirus going down, I have to do a cold hard shutdown and then restart my computer. I can't even do a normal restart. I literally have to hold in the power button because nothing will work.

Symptom B: Rougly once every 1 or 2 weeks it seems that my network interfaces completely go down and I get no network communication at all unless I reboot. It just happened to me a few minutes ago, actually, which is what spawned me to write this post.

I was surfing the web when suddenly I noticed a slow-down in speed. Then 1 minute later all network connections were lost. No HTTP. No SSH. No FTP. Nothing. I tried disabling and re-enabling all my network stuff, but to no avail. I had to reboot.

I didn't have to do a cold, hard reboot like I have to do for symptom A, but I still had to reboot. Once I rebooted, everything now works as normal. This happens once every 1 or 2 weeks.

So...

What do you think could be wrong?

I am running Windows XP Media Center Edition as my OS. I have never had such problems with any XP installation before. The network problem (symptom B) has been going on for a couple of months, and the all-system-failure problem (symptom A) has been going on for about 3 weeks now.

I suspected a virus, but when I scan my computer I find nothing (using Symantec Antivirus, AdAware, and Spybot). Everything seems clean.

Any suggestions? Has anyone ever had similar symptoms?