You have a virus my friend.
What I would like you to do is boot the PC into safe mode...
When that has been done, type in msconfig and go to startup tab
If there is an application that should not be there disable it
Run a spyware scanner if you currently have one/Virus scanner
The virus script is the most simplest script that just frustrates people
If the above does not work. follow this path
type in: regedit
In the Run folder has all programs that start up on startup... if there is one that should not fit, right click and delete the entry.