I can't cut and paste and the mac doesn't see me as the admin

Question

Okay so here are my current frustrations and issues:
1. I can't cut and paste anything! Not from emails, not in documents, nothing.
2. I went to make changes in the utilities and when I started, under my name, it said admin and now it says standard and the computer won't allow me to make changes. I try to enter my name and password and the computer says I am not the admin.
3. I can't delete the "test" user and "guest" user because apparantly there is no admin.
I have rebooted using the install disk and I was able to change the passwords but I still can't get in as the admin.
Is there a way to override this before I a) pull out all of my hair, my husbands hair and the hair belonging to my cat and/or b) before I throw the machine out the window and then have another frustration that the unit is not working?! 

Answer 1

First back up all your data, if you haven't done so already.
Boot in safe mode (shift key down at startup) and check to see whether the clipboard now works. If it does, reboot as usual (not in safe mode) and try again.
Next, boot in single-user mode by restarting the computer and holding down the Command and S keys at the chime, until you see white text on a black background. Wait for the text to stop scrolling, then follow the instructions on the screen, which will tell you run the fsck and mount commands. Be very, very careful to type the commands correctly. After you enter the mount command, please enter this:
rm /var/db/.AppleSetupDone
Then this:
exit
The Mac will now boot up as if for the first time. Go through the setup procedure to create a new admin account with the same name and password as the old one.