Flickering screen, etc.

[Vivacie]

Hello, Computer Hope!

I've went through several topics looking for my problems, but I can't seem to find a solution.
So, please stay with me as I try to explain my situation(s), there are several, unfortunately.

First of all, a few months back (lets say around June) I got a blue screen, which resulted in me having to restart the computer. This happened twice. (Sorry, I don't have caps of it or of anything for that matter.)

After the blue screens came the flickering- usually when switching users. Basically the screen is either, a) black and you can see an enlarged mouse flickering, or b) the monitor has these crazy grey lines and every thing is enlarged and flickering. This has happened quite a few times, and about forty minutes ago. I'm not able to do anything and I have to once again, restart.

Also, sometimes the mouse will move on it's own accord (or just stick for several seconds), this gets annoying especially while trying to ink line-art. Help for that as well?

And, last one, I swear.
I'm using FireFox 3.0.3. When I click on the icon, it takes it at least a minute for the browser to pop up, and after it does my exhaust fan works overtime- like right now, it's extremely loud. Maybe I'm using a bad add-on?

This what I'm using-
Windows XP, Media center edition
Version 2002
Service Pack 2
-Anything else and I don't know where to find it.

And I've been without any AntiVirus products for about a year now.

Any suggestions on what I might be able to do fix these problems?
Please and a million thank yous.

[JJ 3000]

 I've been without any AntiVirus products for about a year now.

This sounds like your main problem. There are a few free anti-virus programs that you can download.

Have you tried a different monitor?

[Vivacie]

Ah, no, I haven't bought/tried a different monitor.
The monitor is not old, probably not even two years, the screen has a nice clarity to it.

Would the monitor affect the processor? As in, making it become unresponsive? I forgot to add that in.

I will download an antivirus program then. =]

[JJ 3000]

I like avast! anti-virus
http://www.download.com/Avast-Home-Edition/3000-2239_4-10019223.html

[JJ 3000]

If your computer came with anti-virus programs pre-installed, and your subscription has run out, then you need to completely remove it before installing another anti-virus program.
Go to Start and then Control Panel and select "Add/Remove Programs". Now select your old anti-virus software and remove it.