Do I need new a new RAM or processor ?

[Doesnotcompute]

My computer was able to play Grand Theft Auto 4 but one day I turned my computer on and tried to play the game and my screen displayed frequency out of range and has displayed this message ever since when trying to play this Game. I have to restart my computer though the power button because I can not exit out of this display. Whats wrong with my computer ?

[JPMiller]

OK, welcome...
A few things to remember, We cant read minds or see your PC from where we are..
There are many reasons this can happen...
First we need some basic info...
What brand/model is your PC?
How long have you had it?
Your using something to write this post so, can you hook another PC to your display to rule out a monitor issue?
More likely this is a video issue, unless your video is onboard and then it could be a memory problem.
If your monitor is showing the out of range error, then it most likely recognizes you have a signal cable hooked to it, but it cant decipher the signal.
I assume the PC powers on and sounds like its loading windows etc.?

[Doesnotcompute]

Its a Gateway GT5014
Ive had it for 5 years.
Intel(R) Pentium(R) D CPU 2.80GHz
RAM:1021.6 MB
Microsoft Windows XP Professional Service Pack 3
ATI Radeon Graphics Processor XFX HD 4650

Its not a monitor issue, the computer does power on and makes the start up sound.

[JPMiller]

Well since its a dedicated card, the most likely suspect is the video card...
Do you have a spare to test with?
In some cases, the issue could be a failing power supply as the underlying issue.
Truth is the average "brand" PC has a life span 0f 3-5 years before it starts having issues that no longer make sense to spend money on...
Anything over a $100 fix, is wasted money in my opinion...
But if you were having no other issues and a new PC just isnt feasible, I'd say start with a new Video card..
It looks like that model has onboard video...
Is the card thats in there an upgrade, or was it bought that way?

If it is truly a dedicated card and there IS onboard video as well...
Turn off the PC, remove the dedicated video card, and then plug the monitor into the onboard VGA port and turn it back on...
If it works fine, then you simply need to replace the video card, or use the onboard if you don't want to waste the money