I am having a similar problem too!  I have been researching on here for a while using a different laptop but I can't quite figure out how to get the monitor on my HP Mini 110 back on.  Can anyone help?

start it in safe mode by tapping F8 when you start it and then use windows system restore to a date before you made the changes.

I have used a Registry workaround that I found on Windows 7 Forum, Clean Install with a Registry Workaround. I worked immediately. I am a female geriatric, so if I can do it it is well explained. Except for one thing.

 After you have downloaded the Registry file, clicked it to 'merge it, the article talks about using an ,Elevated Command prompt'. Just in case you, like me, don't know what that is, it means that only the administrator can write the change. The solution is simple. Point to the Command Prompt (Accessories) with the RH mouse and click 'Run as Administrator'. This takes you in to the correct Cmd screen 

Many people are complaining of the same thing. I first had the trouble when I installed the final Windows Updates. After that I could enter only through Safe Mode. If you can see the screen in Safe Mode apparently it is not the display driver. I could not uninstall the Updates, so I performed a Custom Install following the directions in the Win 7 Forum article.

1. Make sure that you leave unticked the automatic Activate box (at the enter Product number screen).

2. Also, select the third option Ask Me Later for the install Updates, or you will never get to correct the Registry.

3. Activate your product ( you should have your internet connection intact)