playreblox

Okay so I may sound quite thick and I used it. I wanted to "clean vista drive" on "1 pass" and on "free space only. I have I 1gb ram, 70 gb hard drive,32 bit labtop. I had 19 gb of space free on my pc. Then it became 25 gb free when one process finished then it went down to 3 gb free space and I thought something bad was gonna happen so i stopped it. So what was meant to happen. That? and if so why? and would any data remove that i don't want?