I have no experience with gateway computers

best advice i can say is:

check and try to reseat the ram,

check for abnormal HDD sounds,

take it apart and clean any dust IF YOU WANT TO,

check the LCD video cable,

and make sure the inverter is securely connected too and check the motherboards too

google a takeapart guide

also, if under warranty, send it to gateway

Since I wrote this 3 years ago, I figured it's worth cleaning up and revising from the ground up

First, is it a laptop or desktop?

If it's a desktop, try this

Remove the side cover and consider cleaning the dust in the case, and look for a round silver battery on the motherboard, this will be your clock batery, and there is a tab holding it into the socket, which will be bent back to remove the battery, plug the computer in and see what happens

If this fixes it, it will load the default BIOS settings from the factory and should fix the issue, from here you will want to unplug the computer and replace the battery, if it reloads the default settings again, that's OK because of the fact it loses the settings in BIOS if you don't have a battery in

If that didn't work, reseat the RAM as others here have stated too

Next, look at your video, it could be shot

If you're using a AGP or PCI-E video card, remove it and use onboard graphics and see what happens, and if that doesn't work, reinstall the video card and reseat it

If you're not using a video card, get a cheap low end card from AMD or Nvidia and install it;it could very well be dead onboard video too

If you use Linux on this PC, get a AMD card, they're much more friendly with Linux then Nvidia, but if you use Windows, both cards will be good

If it's not your video card, try a new power supply and see what happens, because failing power supplies can also do this too because the video can't get enough power

If all else fails, it's your motherboard at fault

If it's a laptop, you'll have to do more to troubleshoot it

As to a laptop, try this first and foremost, as this will determine your path you follow

Hook it up to a external monitor and see what happens, and use a flashlight to see if you get a image on the laptop

Did it come up on the external monitor with a clean image? It's a bad video cable to the display, LCD panel or inverter fault

Nothing came up, or did it look like you got garbage on the external monitor, distortion and video gliching? It's your video card and you will probably need a whole new motherboard to repair it

If you got a image with no backlight, it's the inverter or display

Start with the inverter, or it's the display

If you got a messy image on the internal display, you may have a bad display cable or panel

Start with the display cable and see what happens

If that doesn't work, it's probably better to buy a parts laptop like yours and snag the display assembly for your laptop and fix it that way if you don't want to find the display on it's own and replace it independently