For everyone having problems deleting files.
 

Vista or Windows 7

Control Panel
User Accounts and Family Safety
User Accounts
Vista: Turn User Account Control on or off
Windows 7: Change User Account Control settings

Turn this off, yes to prompts, restart comp.
Delete+Add any files you need to.
Turn back on if you wish.

Honestly I haven't had this enabled since Vista first came out, and disabled it when I got Windows 7. I have never had a problem installing or modifying any programs. However if I lived with anyone else I would suggest turning this back on, hell I'd say if you don't know what this does turn it back on after.