Actualy XP detects the speed of your processor and if you have anything slower than a 233 it will not install. Also Windows ME has a requirement of 150mhz or higher and will not install on anything slower. I would know because as soon as XP came out we "attained" a copy and i tried to install it on my 200mhz at the time. My dad was chuggin along on a 366 but it was REAL slow. Those where back in the day of course and i would never try to run XP on a processor like that.