Wait Wait, ok here's the deal.
This happened to me once. Dang Detective Conan manga site.
Ok, I now this osunds expensive but the best tihng you can do right now is this.
1: Shut down your computer right now. Actually, google "Reformatting a Computer" first and print out some instructions(or e-mail them and read them on another computer).
2: Go to a local office store or something and get an External Hard Drive. I got a BlackBook myself and I am happy with it. I have episodes 50-200 or so plus a ton of other crud(some Manga files and ALL my artwork which was alot) and didn't take up 1/4 of the HD.
3: Re-formatt. Reinstalling windows doesn't wipe the hard-drive clean. It jsut wipes off all files that didn't come with Windows, but occasionally leavce leftovers directly on the drive in-tact, so those crumbs arn't good and even then it wouldn't squash everything. Follow the instructions, you'll need to reformatt, then reinstall windows from scratch. I recommend making sure you have at least 4-5 hours in case anytihng goes wrong since the proces sshould take about 3 hours or so.
Plug in your external HD afterwards and now not only is nothing taking up room on your computer BUT it's a clean slate with all your stuff saved elsewhere, just in case it happens again.
Also note that now One Peice and your art can be switched to various computers now. Another thing, when you delete programs, Windows jut removes the stuff and writes it as "rewritable disk space" so now you have an absolutely clean disk space.