Hi Vicki,

If the blue screen error occurred right after you installed the Geogebra program and its other dependencies, then the first thing you need to do is uninstall them and restore any recent changes.

Have you tried all the advanced boot options, by restarting your computer and pressing the F8 key?

Here is a list: http://windows.microsoft.com/pt-pt/windows/advanced-startup-options-including-safe-mode#1TC=windows-7

If you can access the Windows safe mode, you can easily perform a system restore and restore your computer to an earlier time.

It is also important that you share the details of the error displayed on the blue screen.

Let us know if the restoration works for you.

James