Some of your symptoms suggest a software problem.
Using the Task Manager, you'll either see some program using cycles,
or the kernel is using cycles.
Assuming the kernel blocks, waiting for hardware to respond, it is possible
for a momentary system freeze to be an issue between the kernel and a piece
of hardware. For example, in Win98, I noticed a networking problem could
bring the system to a stop. If the OS is making 50 tries to read a bad
sector on a hard drive, that might be a reason for a temporary freeze.
Antivirus software is very invasive. To give an example, my antivirus program
seems to have replaced the Idle loop with its own. The HLT instruction is no
longer being used to save power when the system is idle. I consider that to
be invasive, and a waste of electricity when multiplied over millions of
machines. And to top it off, not all antivirus software can be cleanly
removed from a system, which means doing differential analysis with and
without the antivirus product in place is impossible. This is one reason
some people will not have kind words for an antivirus product.
In terms of debugging capabilities, some OSes have more tools available
for observing what they are doing, than others. Without at least some tools,
all you can do is remove stuff and retest, or nuke the install and start
all over again. If you want some tools that can inspect the system, try
sysinternals.com (now owned by Microsoft). There are tools there for
doing the same kinds of things the Task Manager does.
To rule out hardware, you can always temporarily boot an alternate
OS. Examples are Ubuntu or Knoppix. Or connect a clean hard drive,
install Windows on the clean hard drive, and see whether the problem
still exists when a minimum of software is present.
A visit to a site like Castlecops, usage of HijackThis, can get you some
comments from malware fighters. (You post your HijackThis log and they
tell you whether you're infected or not.) They may be able to tell you
whether there is anything suspicious or not.
I use Kaspersky on my system, and I can tell you I've had a hard lock (reset
button), while mixing Sysinternals tools with the antivirus active. (I think
I was trying to use a file monitoring tool at the time.) I know the
antivirus software can lock the system up, if it thinks an invasion is
happening, even when the tools are analytical ones.
Paul
