First thing I would do is goggle registry cleaners.
Select one, and download it.
They are usually free.
Once you have it installed, click on it's desktop icon.
It will show you new and old software, and files.
Remove anything you don't recognize, especially if it is someting new.
Run the full gamit of registry cleaner.
The program should show you software, start up files, back up files etc.
Look at everything, and remove what you don't recognize.
Next, google Dr. delete, and download the free program.
Look through your c drive for files that don't appear to be anything that has to do with the operating system.
The file you will be looking for should have exe after it.
When you find it, right click it and copy it.
Now, open up the Dr delete program, and paste the file name you copied into the box, then click on delete.
Re boot the computer and you shoukld be ok.
Bob.