Open Windows Explorer or My Computer and browse to the installation folder. Right-click the main installation folder and select Properties from the menu. Do you see a Security tab?
If you do, set the permissions for the limited user account to have administrative access to that folder (i.e. "Full control"). Then click the Advanced button and set the option to replace those permissions on all child entries, i.e. all files and sub-folders within the folder that you are changing.
If you do not see the Security tab, go to the View menu and select Folder Options. Turn off 'Simple File Sharing', click OK and then repeat the above steps.
Let us know if that helps