So your computer will not boot to Windows and is hanging at start up with that black screen just staring at you.
Try this solution
- Turn the power off to your computer
- Disconnect every peripheral device ( USB , Firewire , Modem , Network cable , printers etc ) connected to the computer.
These devices , especially the usb ones can cause your computer to not boot due to power issues with the device feeding into your computer.
Then try to start your computer.
If the computer reboots then reconnect the devices one at a time rebooting between connections to find out which device you may have been having trouble with.