This one here:
http://www.testmyhardware.com/

Not sure how well it works, but it looks interesting.

Okie Scott, gonna go download that and see what happens

Oh wait..maybe not....that site got a red flag from Norton!

Uninstall Norton.

Don't get me started on those dang anti-virus programs.

Cooling fans are the most common fail point on computers... They are usually the cheapest quality and fail easily. And YES they can cause performance issues. If a fan fails, excess heat is not drawn away from the high performance components on the motherboard.

Check all fans. Watch them running, listen closely to all of them as they start/stop. With the power off, lightly turn on each of them (both directions) and feel for any "hang-ups". If you suspect any of them, replace with the highest quality replacement you can afford.

Another way you can test/rule out fans and temperature related problems is to either open the case and use an external fan to keep air moving. OR use canned air when the computer is showing symptoms. I always urge caution when using canned air, since I have seen people actually do more damage than good with it (ie... exploded chips from super cooling, by holding can upside down and letting the extremely cold liquid release onto them).

Anti-Virus Programs... The 2nd biggest VIRUS' out there, only beat out by Windows

If you are running Windows 7 there are some pretty good diagnostics built-in. Unfortunately, the results are a bit technical but it does check all the vitals.

In the control panel click "System and Security" >> "System" >> "Performance Information and Tools" >> "Advanced Tools" >> "Generate a System Health Report" if you are up to it.

Scott - lol at your Norton comment! Didn't know you didn't like anti-virus programs! Sorry!

But I must keep Norton installed - I have nothing else to protect my pc and I'm no techie so I'm sure I'd catch something w/o Norton.

Levi - I'm running Windows Vista 64 bit.

I ran the Hardware diagnostic tool thingie and it took a while and I heard the revving up on my pc tower a few times, but all tests passed.

I know I'm not supposed to open up my tower case while the pc is on, but I wanted to see what the noise was.

I didn't know this, but the two little fans are always running - right? I mean, they are running now and my pc is nice & quiet.

So what is it that makes that loud whirring up sound? Is the the fans kicking into a "higher gear"? Or some other device?

Well, I'm going to turn off my pc and clean it a bit. I see a few dust bunnies - not too bad though. I will be very careful w/the canned air

Thanks everyone - I'll be back to see if anyone knows more about the whirring up sound - as I call it.

I'd turn it off Amelia... And install/run it 'maybe' every 3 months or so, as you feel there may be a need for it. I have been "on-line" since before Al Gore invented the internet and have only had 3 virus attacks. 2 came from e-mail and one from FB. I NEVER run Anti-Virus UNTIL I seem to have an issue. Then I clean up the mess and un-install the bigger virus (the Anti-Virus program) until next time.
Why not? I do it all the time In fact, I have a computer on a "test bed" that I bought and it stays on 24/7, with a fan blowing across it. I have also seen some really neat case-less frames that I'd love to use, but can't justify the $$$ expense.

That is a possibility, I have had several computers that used "2 stage" or "2 speed" fans, controlled by the MB/BIOS.

Always a good idea to kill the dust bunnies... One hunting trip I don't go on often enough.

Okay got it cleaned & put back together. I did find one thing...might be really bad, not sure. One of the fans is broken! Not the fan fan fan part, but the lower part that attaches to whatever it is behind it. I'll insert a pic to show:

http://i988.photobucket.com/albums/af1/AmeliaUSA/fan.jpg

If you look at the pic above, you can see the little curved black plastic thingie is broken underneath the fan. I removed the cover and it looks like this:

http://i988.photobucket.com/albums/af1/AmeliaUSA/P1310039.jpg

I was able to clean the thing behind the fan cover & was able to reattach the cover - but only using the top part since the bottom is broken.

Could this be the prob?

Looks like I'll be buying a replacement fan. Any recommendations on brands?

THANKS A LOT EVERYONE! Luv y'all!