I want to build a low power mini-itx pc and I don't know if I want to include an optical drive. All I want to know is if I can use my windows 95 disk and upgrade from a flash drive to windows XP. I want to do the cheapest option as I am on a budget.
Depends on what you want to use the PC for, you can just run Linux on it. Low power usually means not a gaming, just about anything else you can use Widows for you can do on Linux. You can easily install Linux from a flash drive, heck some of them you can just RUN from the flash drive.