Modern technology sucks ass: I can't get my computer to work! (fixed, nevermind)

[HeilSvenska]

I just got a new (used) computer tower by itself, and it worked fine when it was hooked up to my friend's peripherals, but when I took it home it didn't work with my keyboard! It has to do to the fact that my keyboard has a PS/2 connection. So I got a USB adapter, but I can't still log on because the computer doesn't recognize the setup. And I can't use my brand new keyboard because you have to install a new software on the computer. But I can't do that when my mouse doesn't work. WTF. So I wasted money on two adapters for no reason. Why can't things be just simple? And what happened to plug and play?