I know my system specs are very important in order for you to answer my question but i just couldn't get them and i don't know how to.

I have a problem with games. My PC meets all the system requirements must games need but for some reason when i try to play them at the highest quality possible something happens. They either run slow,get a black screen or don't star at all. All the games(HL2,F.E.A.R, CALL OF DUTY 2) i wanna play run fine but when i try running them at a screen resolution of 1280 by 1024(highest resolution possible on my display) something like i mentioned before happens. I went to this web site, http://www.srtest.com/referrer/srtest and checked if my PC was able to run the games i wanna play and it said it was more than capable to run them. The most common problem i get is slow frame rate. When running games at low quality it stays around 60,59,57 frps but when i kick it to high it goes down to 4 frps. To make things clear all i wanna do is to increase the frame rate of games running at high quality. Anything you want to tell me, tricks, methods, advice is appreciated.

i dont know if this is helpful but i got this about my pc from that site:

CPU
Recommended: Pentium 4 or Athlon XP
You Have: 2 processors running - Intel(R) Pentium(R) 4 CPU 3.00GHz PASS
CPU Speed
Recommended: 2.2 GHz (Intel) or 2200+ (Athlon)
You Have: 3.0 GHz PASS
System RAM
Recommended: 512 MB
You Have: 1022.1 MB PASS
Operating System
Recommended: Windows XP
You Have: Windows XP Professional Service Pack 2 (Build 2600) PASS
Video Card
Recommended: 100% DirectX 9.0c compliant Video Card with Hardware T&L and 128 MB
You Have: RADEON X600 Series (RADEON X600 (0x5B62)) PASS
Video Card Features - Minimum attributes of your Video Card Video RAM: Required - 128 MB , You have - 256.0 MB
Video Card 3D Acceleration: Required - Yes , You have - Yes
Video HW Rasterization: Required - Yes , You have - Yes
Video HW Transform & Lighting: Required - Yes , You have - Yes
Vertex Shader Ver.: Required - 2.0 , You have - 2.0
Pixel Shader Ver.: Required - 2.0 , You have - 2.0
Video Card Driver Version (DirectX)
Your driver version number is: 6.14.10.6601
DirectX Version
Recommended: 9.0c (included)
You Have: 9.0c PASS
Sound Card
Recommended: Yes
You Have: SigmaTel High Definition Audio CODEC PASS

That is what it told me if i try running DOOM 3. i dont know if it will work that way because i dont own DOOM 3.

First off thanks for that link/scan! Very useful.

My first guess is that although your computer exceeds the requirements the relationship between your Graphics Card and Monitor may not.

Have you checked the setting via Control Panel > Display > Settings > Advanced > Monitor > Screen Refresh Rate

screen was set 65 hz now it's at 75hz and it increase greatly. i cant get the frame rate i want but they run more smoothly now. they run well at 1280 by 1024 but only if i lower the quality. that was very helpful thx but if you know any other way dont wait to tell me. it'll be appreciated too.