i don't know why, but old deleted files keep reviving themselves and starting to appear everywhere.. is there a prog that can delete the deleted files, or revive some lost ones if you accedently remove some?

Oh, and a funny thing.
I was enjoying my XP, doing the "casual" things when suddenly the "your c:/ drive is low on space" thing pops up. WTF? i never use C:/ for dl, and C:/ is only my windows/ system drive..
So i go to c:/ and search for new files and i spot a new txt file.. so i open it up, and it's empty.. ok.. so i check the filesize, and you wont believe it.. + 800MB!!

a goddamn empty txt file took more than 800Mb?.. wtf is that all about?