How To Share Scanner Driver Why Is System Restore Not Working?

Why is system restore not working? - how to share scanner driver

My desktop (WIN XP Pro), have changed the PC settings. I am now prompted for a password - I know not share with anyone - before Windows has loaded and completely closed, the situation changed to another, now says blah XP Pro ... I've never been a password, and pass the first message by pressing ENTER.
Apparently last Thursday. The only difference I have on that day to install a driver for my scanner was. I tried to restore the system, just keep saying "no work, no changed files.
What has caused this change and how can I fix this please?
Thank you.