On Monday night my PC was working fine and closed down with no problems. It is a HP Envy - H8 1485ea, running with Windows 8,1. This was a downloaded upgrade, which I installed ages ago, upgrading from Windows 8, which was pre-installed on the system.
When I switched it on on Tuesday evening it started repairing the drive (I assume this was chkdsk or something). There was a message displaying the % of the disk it had completed. When it reached 100%, after about 40 minutes, Windows tried to start, but went straight to a message saying "Your PC ran into a problem and needs to restart. We're just collecting some error info and will restart for you". The error code it advises me to check online is 0xc 000021a. Then, after a few seconds, it went to a black screen with the message "ERROR: No boot disk has been detected or the disk has failed".
This "PC ran into a problem" and "ERROR, etc." is all I get every time I try to switch it on.
The problem is, I can't even access the repair menu, or start it up in safe mode. I don't have a recovery disk/usb. I have tried F8 and shift+F8, but it is always the same. It just won't boot up.
I've tried leaving it for 24 hours and starting with all peripherals, etc. disconnected, except for the usb that runs the wireless mouse/keyboard - but still no access.
I can't understand how it can be fine one minute and totally inaccessible the next.
I've spent hours googling this but all the solutions seem to assume that you can actually boot up the system and get to the recovery/repair page.
Is there any way I can get to at least the recovery tools or safe mode to try and sort this?
I rely heavily on this PC, so a quick reply would be much appreciated.