Computer Problem and Advice needed!

Hi,

I've been using this website and forum for years to find out bits of information etc, but i've finally needed to actualy post.

I bought a gaming PC (the Titan Thor) from overclockers about a year and a half ago, I bought it as I thought it would solve all the low fps issues i was having with my old, ancient pc before that.

Anyway, i thought the new pc was good but not as good as i thought it would be for the ~£800 I paid for it. At the moment, games like Black Ops, Age of Conan, and the Rift Beta don't run too well at all. I have a few friends that have almost identical pc's to mine, but theres has a slightly better processor.
They don't seem to have any fps issues but my fps always seems to give me lots of slow down! I've done some research and found out about using the Driver Cleaner tool from 3D Guru, which has improved my fps slightly.

The only drivers I ever check for updates are for my graphics card. Should i be getting drivers for all of my pc componenets? (CPU, RAM...etc) I know very little about keeping pc's up to scratch after I've bought them.

I was hoping any of you might know any tips on what i could do to possibly increase my fps and how i can look after my pc abit better! - And I plan on upgrading a part of my pc, which components should I look at upgrading?

My specs are:

CPU- Intel Core 2 Quad Q8400 @ 3.20GHz (overclocked from 2.66GHz by overclockers when I bought it)
Memory- 4GB DDR2
GPU- Powercolor ATI Radeon HD 4890 Plus 1024MB GDDR5 PCI-Express Graphics Card
Motherboard- Gigabyte
Case- Antec 902
OS- Windows 7 Home Premium 64 bit

If you require any more information please let me know

Thanks for reading!

Oliver

i have played black ops and age of conan on a lower spec than you and my computer can run these games fine surprisingly on high settings. i know black ops had problems with fps but they fixed that. has your computer had fps issues since you bought it or has it progressed over time ?