when power fails during the hard disc access, it leaves the file locked and corrupted. The corrupted file will occupy the disc space where you can not over-write with a new fresh copy even if you repeat uninstall/reinstal. you have to remove that devil first. If I were you, I would do a thorough disk check first before installing or uninstalling any updates. you may find free software to check disk and get rid of those corrupted file if you can not solve the problem using chkdsk /f.