Doesn't look too bad to me... alt+tab to switch. Restart if you haven't tried already, if you have tried already, restart and hold ctrl while it's booting, should load it without the modifications. Then uninstall. Also you're having permission issues, use an Administrator account. Edit: Are you trying to delete a theme? If so you're doing something VERY wrong. There are no themes involved with this. I have no idea where you even got that from... To uninstall properly, you'll need an admin account, the AGTweaker GUI, and then you click the X in the bottom right corner of the GUI and restart. Also, I tried restarting holding down Control. Nothing happened, booted up like normal.