|Get into safe mode then click start then run.|
Type msconfig and click ok.
Go to the start up tab and disable everything in there by unchecking all boxes.
Apply and ok yourself out. You will be asked to restart. Do so. All being well Windows will start. Now again open msconfig, and one at a time, re-check those boxes. Each time you check one box, restart the computer. You will know which is causing the problem when you check the box of the offending program.
Computers... designed to entertain,help with work but most of all to frustrate you!