Hi there....it could be a number of things...
You can try these....

**See if you have two confilcting pieces of memeory installed. If they are the same type, size and brand then they should be fine.... please see how to open a computer case safely here ( http://www.tips4pc.com/... ) so you won't damage your computer.
**Check to see if your monitor plug is in securely.
**If you have a LG monitor change the blue plug to the black one that comes with it...
**try installing your graphics card driver again.
Smile, it's fun...

Hello, the first thing you should do is to download service pack 3, and then check the configuration in power option through control panel and configure it to your own taste. The process is: START--CONTROL PANEL--POWER OPTIONS--, on reaching here, set POWER SCHEME and ADVANCED. If the problem still continues after these configurations, remove your battery and fix it back and follow same as mention above.

I did have the same problem... Most likely it's problem is hardware based because I have the same problem while playing games or any app that relies on the video card...

Definitely the cause of the problem is not the memory cause I've replaced mine recently and I'm still having this problem.

My specs are:
-Pentium 4 2.6GHz (Northwood, purchased 2009 as surplus since it's very expensive to build a new system)
-(Previously I had a Celeron 1.7 GHz)
-ECS 648FX-A2 (Purchased around 2006)
-1GB DDR400 RAM (Recent 2009, You can just imagine how hard it is to find this one nowadays and how expensive it is byte-for-byte with DDR2 RAM)
-80GB SATA (late 2006 I had a PATA drive but it has low capacity back then)
-1 Samsung CD-RW PATA (2004, you can imagine how old it is right now)
-1 LG GH22LS50 SATA (recently bought, I've just dented my wallet for this... I was thinking about compatibility If I can build myself a new system to replace my old one, oh... I cant cause I'm poor and I can't even buy myself an OS)

My problem, i think, was my motherboard... I've played with the power by using an under-rated power supply (around 250W, it was the old standard when P4 first came out but recently buget boards require more than 300W) since I wouldn't want to replace an insigificant part of the PC and used it and attached a lot of fans which caused my hard drives to fail back in 2004 and 2005. I abused my warranty well and I decided to remove the fans.

The screen goes blank thing only occurs usually when I have my PATA drive attached. I don't think my motherboard is sufficient in handling SATA since this is a legacy system and only a cheap response in the recently emerging SATA standard. I had to pin my HDD only to use the SATA150 since SATA300 will make my system unable to run. It's also unwise to use both PATA and SATA at the same time cause this problem usually arises when they're both attached.

Enough explanation... here are some tips:
-Clean the motherboard if it accumulates dirt. Dirt causes static and static damages the board.
-Do not make your board exposed, outside dirt may damage your board worse than what heat can do.
-Its unwise to mix SATA and PATA devices... they are supposed to be cross compatible with each other, it may cause problems with the southbridge chipset especially with cheap old motherboards. Use either pure PATA or pure SATA devices. I had a SATA HDD and a PATA CD-RW and I encounter this same problem but by using only the SATA HDD, I don't encounter this problem. Recently I've bought a SATA DVD-RW drive and I'm still testing to see on how it goes. For now, I am not anymore experiencing the problem that you encounter right now.
-It could be a problem with the Video card... well if eventually at some time I reencounter this problem... I would put the blame on the video card. Clean your video card and shine its contacts with a pencil eraser.

Suggestions:
-Check your Motherboard or video card... OR BOTH.
-Clean your components with either a vaccum, duster, or something anti-static. don't use chemicals or other wet or with corrosive substance cause it will damage your board.
-I suggest Isolating the problem... If you're a techie, try testing your components with other system and concentrate on the motherboard. if you can, you can borrow a board (with the same chipset cause other chipset will cause your hard drive to become unreadable). and placing all your old parts with that board... If it doesn't work, you can borrow a video card and .... do stuff.

I hope I help