Yirrk =)
You wont belive how easy it is. First of all switch off your computer and then turn off the power supply at the back and unplug the power lead.
Then remove the screws that are holding the side of your case on (usually just 3 or 4 screws) and the side of your case should just slide off nice and easy.
Then you can take a look inside and say wooow cool
I remember the first time I upgraded a PC I was damn nervous about breaking something, but I will tell you now the components are well made! They arnt fragile at all, so dont be nervous about breaking things
I have never ever broken a PC part.
You should be able to see where your current graphics card is (you can tell which one it is because your monitor cable will be plugged into it. There is just 1 screw holding it in, unplug the monitor cable (and any other cables that might be attached) remove the screw and just pull it out. Dont be affraid of breaking it, you wont =)
However, if the monitor is plugged into your motherboard (the main circuit board that everything else is plugged in to) then your pc has got a graphics card actually built into it which cant be removed. Fear not, because you can add in your new graphics card and it will override this built in (on-board) graphics chip. If you look at the slot that is nearest to your Power Supply (easily identified as a big metal box that the power lead was plugged in to) you should see that the slot is the perfect size for the terminals of your graphics card to slot in to. However, there might be a metal plate at the back which prevents you from putting your card in! If this is the case, undo the screw and remove the plate. If the plate appears to be actually fused or welded to the case, you need to punch it out by carefully stabbing it with a screwdriver and then twisiting it backwards and forwards until the bits of metal that held it on break. Then, carefully position your graphics card above the slot and by applying pressure at both end with your thumbs, push it in. And when I say firmly, sometimes if the slot hasnt had a card in it before it can be a bit harder to push it in. You gotta break that bitch it
but seriously, dont be scared of breaking it. In the past I have pressed graphics cards and memory dimm's in so hard that I have been left with bruises on my thumbs and they dont come anywhere near breaking =)
So then, fasten your new card in with the screw that you removed and plug all the cables back in (leave the side of your PC off for the moment until its all working, in case you need to go back in there for any reason) Also, it is possible that your graphics card will need additional power, if this is the case, then just plug in one of the spare power leads from your power supply. Dont worry, they are all standard voltages. Read your manual about it!!!!
Basically, you cant plug the wrong thing into the wrong place. you just cant do it! everything in a PC has its own special connector types and fittings to stop you from doing that.
Good luck, let us know how it goes, and before yo do anything, go now and READ THE MANUAL!
seriously, im not being rude here, there isnt much to read, and it will help you out a lot!
