Sleep issue with Vista 64 bit

Hi,

Recently I've been having problems with my computer, I was hoping someone here could help. The problem first presented itself by showing a bunch of lines on my monitor screen. This would happen during a video game, and once in a while at random. The only way to get rid of it was to turn my computer off and then back on by it's power button.

Eventually, a second problem came up, where when I would pull up a certain program, the monitor would just go to sleep. The computer wasn't asleep, only the monitor. And when I would click the mouse, or press a key on the computer to try and wake the monitor up, nothing happened. So I was forced to turn the computer off and back on with the power button.

This happened for a while, and I went to Gateway's support center 'chat with a tech' thing, and they told me the only solution was to perform a system recovery. I wasn't happy. However, I went ahead and did so, wiping the computer.

However, this did not get rid of the problem with my monitor going to sleep. I find that if I let my computer pull up a screen saver (any of them, it doesn't matter which), the monitor goes to sleep. Not the computer, just the monitor. I've also tried to open videos in fullscreen mode, but that also puts the monitor to sleep.

I also found that when opening a small third party art program, the lines popped up on my monitor again. So I got rid of the program, and haven't had the lines show up again.

I came here to ask if there's something I can do. I searched my problem here on the internet, and it seems like a lot of people have had the same issue.

I'm using a Gateway FX 6000 series computer with a Vista Home Premium 64bit operating system. My video card is an ATI Radeon HD 4850.

(I apologize if this is in the wrong forum section!)

I'm not sure if I have the latest video drivers installed or now, how do I find that out? I also don't know if I have an onboard video connection, how do I find that out?

Also, how do I get the latest drivers if I find that they are out of date?

I clicked the link, but I'm not sure what I'm doing next is correct. I went to 'support & drivers', then I went to 'download graphics drivers'. On that page, I chose windows vista 64 bit edition as my OS, and then radeon as my product family. I'm assuming I want to choose Radeon HD 4800 series as the product, is that correct?

And when I go to download the driver, do I want the full download or the display driver only download? I'm sorry for all the questions, I just want to be really thorough and make sure I don't mess anything up.