That's ok. I was joking myself. If the o/s that came with your compaq says it is for compaq only, you will probably have to get a new o/s. The first time I built a computer, it started as a mobo upgrade for a Hewlett Packard computer. All said and done I had to get a new o/s. But I'm happy I did it. And if your happy with your case, psu, ram, and so on you can just upgrade your mobo and cpu, (and o/s). Being factory built though, you'll more than likely want a bigger psu. The good news is you can find a pretty good case and psu combo at a pretty good price. And when you buy a new mobo, you'll probably want faster, better ram, the new board may even require it. Also. if you buy an oem version of the o/s, you can get it for about half the price of a retail version. But, you probably already knew that.
<font color=blue>GOD BLESS THE U.S.A.</font color=blue>