Does this computer have a video card?? I know nVidia cards can rotate everything 90 or 180 or whatever. Right-click on the desktop and it'll say "properties" at the bottom. Click props and you should get display settings. The tab on the right is settings. Click there and it should tell you what vid card you have. Clicking on Advance should get you to several tabs. One is the vid card. Maybe GeForce or something like that. Clicking on THAT should get you several choices on the left side. One of them being NVRotate. From there, the screen can be put back right.
I hope this is the fix.
Question is.. how the HECK did he get in there??