OK as you have managed to get to the desktop lets run a quick programme to see if I can spot the cause
Please download Farbar Recovery Scan Tool and save it to your Desktop.
Note: You need to run the version compatible with your system. If you are not sure which version applies to your system download both of them and try to run them. Only one of them will run on your system, that will be the right version.
[*]Right click to run as administrator (XP users click run after receipt of Windows Security Warning - Open File). When the tool opens click Yes to disclaimer.
[*]Select both shortcut and additions at the bottom
[*]Press Scan button.
https://dl.dropboxusercontent.com/u/73555776/frst.JPG
[*]It will produce a log called FRST.txt in the same directory the tool is run from.
[*]Please attach all 3 logs generated.