|I had NO problem locating that information. Perhaps you need to learn how to use Google.|
As riider has pointed out, that is the last thing your may want to do.
Windows 64 doesn't tell us much. There are at least three PC versions of Windows that came in a 64 bit version.
If you still wish to perform a factory reset then click on the link below to learn how.
Otherwise post the computer model, type (laptop/ desktop/ netbook, and what issues you are having that you feel warrants the reset.