Hi all, long time reader, first time poster! So, here's the rundown. I partioned my hard drive, backed some stuff up, and reinstalled windows7. Noticing a lack of space, I tried to delete old windows files, and wasn't allowed to. Found a nifty little script that allows one to take ownership of said files. After running it, I could no longer update windows. Tracked that down, can't remember exactly what I did, I think I had to take ownership of a particular file, or delete a file, something like that. Its working, but I can't re-install Microsoft security essentials. It was working, but not updating, so I uninstalled it and tried to reinstall. I keep getting error code 0x80070645. Did all the stuff found on Microsoft’s website, deleted all the right registry files, deleted folders, ran Microsoft’s fix it tool, ran their tool for install and uninstall problems, etc., it just won't work! I think running that "take ownership" program screwed my computer. Am pretty close to just saving what I want to keep on my "D" partition, and formatting "C" and reinstalling windows7. But, remembering the geniuses here at bleeping computer, I thought I'd see if anyone here had a solution before I went through all that work and service pack downloads (slow internet). So, any ideas?