Computer stuck between turning on and starting windows

Hello Ask,
We are sorry to know that you are unable to restart the computer. To fix this issue,we suggest you to restart the computer in safe mode. Please click on this link for the steps to restart the computer in safe mode http://avgclick.me/rebootintosafemode
Thank you.

The avg free tun-up tool asked me to restart to do some diagnostics which could only be done at windows startup. The computer has now been running in about 5 hours with a black screen.

I have tried force shutting it down and turning it on again with the power button to no effect.

wtf?

how can I get back to actually using my computer?

Hello Ask,
We are sorry to know that you are unable to restart the computer. To fix this issue,we suggest you to restart the computer in safe mode. Please click on this link for the steps to restart the computer in safe mode http://avgclick.me/rebootintosafemode
Thank you.