What help do you require?
Choosing 1? Installing it?
If choosing it, download and install speccy and run. then post the readout here (screen shot is probably best). Tell us what you wnat it for ie, gaming, etc. and more specifically what apps i.e. Half Life 2 etc. Photoshop CS5 etc.
Tell as much info re. the motherboard, and power supply as you can.
Installing them is relatively simple after that.
Turn off and unplug your computer then open the case.
Use an antistaic strap (Couple of quid of ebay) remove the old graphic card and bung it in an antistaic bag.
Get your new card slot it in, screw it in and then clip any power connectors required.
close up reconnect and turn on.
Install included drivers, restart and you should be done.
Hope this helps,
