My computer, a Microsoft Windows XP Media Center Edition Version 2002 Service Pack 2. It's manufactured and supplied by Packard Bell Intel Pentium 4 CPU 3.06GHz, 512 MB of RAM.

Basically, it does this and its annoying. Its a surprise that i managed to write this message without it freezing on me!

Please help

What screen saver settings have you got up and running, do you leave it for a minute and it turns itself off? If so check the power management settings, left click on desktop then properties then screen saver tab, then power management.

Thanks for replying. I've removed the screen saver and it's still going off & on!!

Is the monitor cable fully plugged into the monitor port?
Does the monitor freeze, or does the entire computer?
If it is just the monitor freezing we can limit down the possible errors.

Its just the monitor, but then, i can't do anything without the screen. NExt time it freezes, i'll try inserting a music CD to see if it plays.
The wires are all fully inserted.

Are you connecting the monitor through a Graphics Card, or motherboard monitor port?

Is there anyway/where i can find out which it is?

Well look where your monitor plugs into, if it is near the bottom of the tower (if it is a tower) there should be a series of holes that have a metal bar across them. These are the PCI/PCI-E output holes, if it is plugged in there, it is through a graphics card.
If it is anywhere else, it is through the motherboard. If you are unsure still, either take a pic, and attach it to a post here, or look through google images:
http://www.systemaxdev.com/productmedia/htmlimages/cten/Lenovo%20Desktops/Lenovo-3000%20J105-back.jpg
If you plug your monitor into the port labelled 'VGA' on that image, you are using motherboard graphics.

Thanks again. It wasn't through the graphic cards section, so it has to be a motherboard.

Well, unless your motherboard is totally buggered, this problem points to your monitor causing your freezing problem.
Are you able to try this monitor on any other Computer to check that it is not the VGA port at fault?

Also, if you have a spare monitor around hook it up and see if you have the same problem.
Giddyup