formatting

Hi .

im a total noob when it comes to computers .
I want to clear my hard disk I want to start fresh cause my computer has been running slow .

How can i do this can i just format the HD or will that remove windows as well ?

thanks

>>2
>>3

Fails. All formatting does is replace the file system. The data's still there; it's just unaccessable, at least by typical methods. The disk is by no means blanked.