Windows Vista Vista premium reverted to Vista basic

My friend has installed Vista home Premium but for the last few months it has reverted to Vista home basic. He says he must have pressed something by mistake. How do we get it back to Premium, please? Do we need to reinstall Vista? How do you think it happened?

 

You say ‘reverted’ which suggests it was upgraded from Basic to Premium, is this true?

To determine the version, go to the Windows Orb (Start), type winver and press Enter.

To enable or re-enable Aero Glass, here are a few things to try:
1. Sometimes simply going to Control Panel > Classic View > Performance Information and Tools solves the problem. If there is new hardware, just click ‘Refresh Now’ or ‘Update my score‘.
2. Right-click the Desktop > Personalize > Windows Color and Appearance > open Classic Appearance. Is Aero highlighted? If not, click it and Apply > OK, etc.
3. Right-click Computer > Properties and under Tasks select Advanced System Settings (Continue if UAC is enabled) > Advanced Tab then Settings alongside Performance. Visual Effects Tab contains a list of Options, are they all ticked?
4. If you have upgraded from XP to Vista, you may have to download the driver for the graphics card and run the Windows Experience Tool to rectify the problem. This is done by going to Control Panel > Classic View > Performance Information and Tools and click ’Update my score’.

 

vista reverting

Thanks for your assistance. I did a system restore and then got aero back up for him. He is well pleased now.
Joan