I can't defrag anymore. Disk Defrag, Disk Cleanup, as well as notepad and some other basic Windows stuff has been gone for over a year now. I believe it was due to a virus. Any way to get them back? I dunno how this could've happened. It's a pain.
I'd say a reformat would be a good choise here.
That would make sure that there isn't any viruses left and would reinstall the windows (including all of the applications)
Also just reinstalling windows would probably bring them back, it would not delete anything else from ur hdd, just take out windows and put a new one in there. (u will need to reinstall all of the programs)