Installing Windows Vista after Ubuntu?

I have a legitimate version of Windows Vista that came with my desktop. A few months ago, I installed Ubuntu (the OS) on my computer as the ONLY operating system instead of dual booting. Well, after a few weeks, I realized that I should have dual booted because I could no longer play the Sims 2, Maple Story, and many other games that I enjoyed playing. I bought a laptop soon after. Its been a few months since even touching my Ubuntu computer and I decided to try booting the computer from my Windows formatting disk. THIS DID NOT WORK. When I restart, it says "Press any key to reboot from disk" and I press keys (more than one after a few tries. lol) and it just load Ubuntu like normal. Can anyone tell me how to fix this problem? Has anyone had any luck re-installing windows after Ubuntu. I would be willing to just make my system dual boot, but I need to be able to run my Windows programs again! "Wine"(the program that is supposed to run Windows programs, but they don't tell you that it is only a limited amount beforehand) is just not sufficient.