I have Windows 7 and my User name is has Standard User rights.
1) I had logged with Administrator login and tried to change my user logins rights from Standard to Administrative, but could not do so as the “Change User Type” button was not enabled. How can that button be enabled to invoke Administrative rights or how can I change my user rights from Standard to Administrator?
2) My desktop is not accessible and visible. That is, while saving anything, I cannot do so at the desktop.
3) The drives C, or D or E is inaccessible for saving anything.
what version of Windows 7 ?
are you on a network or even a domain ?
(I would not expect so many drive letters on a home PC unless DVD drive is E
Is it your own PC ?
If the system has been locked down you will have to ask whoever locked it down to help
If it is your home PC with Windows 7 Home and you can get to an admin account you can create a additional account (admin or standard) and if that is working transfer your data over to the new account.
using standard account when browsing Internet is safer as more likely only your account gets corrupted by malware.