PC won't boot anything but Ubuntu

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http://askubuntu.com – Well, I decided to give Ubuntu 12.10 a try but really isn't for me, mostly because I'm a gamer at heart and the game selection on Linux is very limited. :P I want to revert back to Windows 7 but I can't seem to be able to access the recovery partition on my Desktop. It's an Acer, so the Alt + F10 combo should trigger the recovery management during the boot, but for some reason it doesn't: the PC goes straight into Ubuntu. I've tried reinstalling Windows from a DVD but it looks like the computer is ignoring whatever boot command I give it. I changed the boot order inside the BIOS, I tried to (HowTos)