What is a good free program to delete files from my PC? (Vista)

I am selling my pc and getting a new one, problem is people can easily find my deleted files (using recycle bin doesn't actually remove them). I've seen a bunch of programs that would do the trick...only thing, though is I don't want to delete everything only the stuff I have deleted already. It won't be until another 3-4 weeks until I can get it sold, but I want to remove private stuff before then...only thing that will be left are the games I have installed. I'll remove those before I sell it, since I'm sure the company I'm selling to doesn't want a bunch of games installed.

Any programs that do what I want? I tried bcwipe but its incredibly slow, 1 week to delete everything and I'm sure I can find better programs anyways.

Thanks :)

As I said, though...I just want to make sure the files I deleted are very unrecoverable. I don't want the stuff I'm leaving on my pcto be deleted...I have some games and a bunch of other files I still need to save onto other hard drives. I will reinstall in a couple weeks, but I've deleted everything that I want off...but it would still be easily recoverable and I have some private stuff on there. Reinstalling doesn't fully delete the files either or make them harder to get back, at least thats what I've researched while on google.

I was thinking of using a file shredder that deletes "deleted" files, a good free one. Not one that erases everything.

http://www.portablefreeware.com/?id=1167

But basically such programs are slow. They don't just overwrite the content of the files with zeroes, they overwrite the file repeated times with different bit patterns. Making it impossible for storage specialists to recover informatio. Of course a non-specialist would not be able to recover after the first overwrite.