System Usage from Most to Least Important: Gaming, Browsing the web and Watching movies
Buying a monitor: No
Parts to Upgrade: GPU and CPU if possible
Need to buy OS: No
Preferred Website(s) for Parts: None as I prefer to buy locally
Your Monitor Resolution: 1920X1080
Additional Comments: Upgrading at the best bang for the buck
Why am I Upgrading: I want to game at 1080p but do not want to rebuild a new rig yet
Current System Specs:
CPU: AMD Athlon X2 7750 @2.7Ghz with aftermarket Cooler Master Fan
Motherboard: Biostar GF8100 M2+ TE
RAM: Kingston DDR2 3GB (2.75GB available for use only as 0.25GB used by on-board graphics)
Graphics Card: Onboard Graphics
HDD: 500GB Western Digital Blue 7500RPM Sata
Monitor: Dell U2312HM
OS:Windows 7 Ultimate
Well I'd recommend getting a graphics card with your whole budget and waiting until you have more funds with the rest of it. £200 just isn't going to get your system upgraded enough. What I'm suggesting is what I did, which is basically putting up with a slow computer until you have finished the "rolling upgrade". It spreads the funds over a long time.
I'd get the best graphics card you can afford and put it into your current system (if the PSU can handle it), then wait until you have more money to spend. Then when you do, get a nice modern processor. Again, wait until you have money then buy a nice modern motherboard that's compatible with your chosen CPU and finally get some RAM that's compatible with your new CPU and mobo.
The hard disk isn't too bad and you'd still keep all your data including the OS, but you might want to get a new power supply depending on how old and how powerful it is.