艳阳天

in that case, i would advise you to run it in a "separate" system. you can choose to dual boot (uses hard disk space, but at least isolate the systems). in short, you have two operating systems in one computer (for example, XP for gaming, XP for normal things), and so you will choose which one to go at boot up. or simply reboot.

it would have been even better if you get virtual PC (free), but i dun think virtualisation is a good idea considering you are doing gaming, as it requires very large resources and specs, and i dun think running games in a virtualised environment is such a great idea.

the other thing that you can consider, is to make an image of your disk whenever you are up to doing something "big". two bigger makers are symantec ghost and acronis trueimage. so you simply "photograph" your hard disk before you do anything bad, and when things go really bad, you can put back that "photograph" of your hard disk to "roll back" to what it was. if you go this way, you should have separate partitions for your programs (system) and data, since most likely you should only be imaging your system and not your data (since data changes so often).
 

the easiest thing is, get my own computer and not to mess up with my dad's computer anymore!
I think gaming is the main problem, I should stick to consoles and don't do anymore PC gaming.