How To Diagnose a Suddenly Slow Windows Computer?

Ensign Taco writes "I'm sure nearly every one of us has had it happen. All of a sudden your Windows PC slows to a crawl for no apparent reason. Yeah, we all like Linux because it doesn't do annoying things like this, but the Windows desktop still reigns supreme in most managed LAN work environments. I'm running XP with 4G of RAM and a decent CPU, and everything was fine, until one day — it wasn't. I've run spybot, antivirus, and looked at proc explorer — no luck. There is no one offending, obvious process. It seems every process decides to spike at once at random intervals. So I'm wondering if there's a few wizards out there that know what to look at. Could this be a very clever virus that doesn't run as a process? Or could this just be some random application error that's causing bad behavior? I've encountered this a few times with Windows PCs, but the solution has always been to just add more hardware. Has anyone ever successfully diagnosed this kind of issue?" And whether such a problem is related to malware or not, what steps would you take next?

Comments

Check Your Hard Disk

[JackStrife17]

In my experience, sudden unexplainable slow performance often ends up being a hard disk issue. Are you seeing a lot of hard disk activity?

People often assume that such problems are much more malicious than they actually are. I'd check to make sure DMA is still active on your primary disk and grab a copy your manufacturer's disk check utility.

CPU issues?

[grasshoppa]

I've had this happen as well, although under somewhat different circumstances. I've always believed it to be windows doing something funky with the processor; somehow winding it down a bit. I know current processors are capable of this, so I always suspected it was windows doing something like that for some unknown reason.