Thought this may be helpful to a few people who are looking at buying a new graphics card for there computer.
Which One?
Chances are you are wanting to buy a better graphics card for either gaming or some kind of program which requires a high end graphics card. My best advice for this is not to look at which graphics card is on offer and hope this will do everything you need it to, but to look at the programs requirements to run the game or program. You will sometimes find that they will have a website which can recommend a graphics card which will work perfect for the game and/or program you are wanting it for.
Found a Graphics card now what?
Don't be so eager to just put this new piece of equipment straight into your computer. I have spoke to a few people who have bought some new hardware; like a graphics card and all there computer will do is blue screen randomly.
All graphics cards require a certain amount of power to run correctly otherwise to protect itself, the computer will shut down and display this blue screen error message.
On the new graphics cards you have found, find out how much power is needed, It will usually recommend an ideal power supply (E.g 400W, 450W, 500W etc), at a minimum you need what the graphics card recommends but ideally more will make your computer more future proof if you need to upgrade anything else.
Installing the new graphic card:
I would never say DO NOT INSTALL YOURSELF! however i would say be very careful, with changing a graphics card there is a few delicate obstacles in your way for example the CPU, Memory and motherboard. So just be wary and try to keep your self earthed so there are no static damages to your computer.
Drivers?
Great now you have your new graphics card installed you need to ensure you have the latest drivers installed. To rule out any issues of the drivers conflicting, I would recommend uninstalling any old drivers before installing the new ones and remember to check for any updates as there may have been a small bug which has been fixed in a driver update (Most drivers software gives you the option to check for updates so you don't need to search the Internet for them).