My young son has a new netbook. Running Windows Vista Home Basic.
When he plays on it he somehow accidentally makes the screen go to portrait orientation (I assume to allow book like things to be read!) Also the mouse orientation seems to be opposite its usual setting- neither normal for Landscape nor correct for portrait.
Go back to normal mode (not safe mode). Right-click on the desktop and select properties. If there is a control panel specific to your computer model, check there. Also, what’s the model of the computer? I can look up the manual online.