Start Your computer with "Windows Advanced Options" , Select Safe mode- Once you reach upto Login screen or Logon Phase- Press - ALT+CTRL+DEL - Once you get Tast manager Windows - Click on File- New task - Type- Msconfig- GENERAL TAB- Select- Selective Startup- Uncheck - Load Startup items, SERVICES TAB- Check - Hide all Microsoft Services- Click on Disable all- Click on Apply, Click on Ok, Restart the computer, See if you are able to boot up properly, if yes then First Enable all the services, and restart check for the problem , if Not Select Startup items- 2-3 at the same time and check.!! See it will work!!!