Review http://support.microsoft.com/support/kb/articles/Q221/5/12.ASP to use SCANREG /RESTORE to go back.
I use WindowsME and have encountered a problem I cant fix. The image on screen has got much bigger - for example the desktop shows the icons almost twice their usual size, and material displayed on the screen at other times is only partially visible on the screen when, due to it's greateer size, only the central part of the page can be viewed. When this has happened on two previous occations, some time ago, I fixed it by going to restore point - but I have just discovered that my computer has stopped creating restore points. Can anyone help with this problem/these problems???/

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic