Black Screen with Cursor, tried many suggestions but still cannot boot

I have read and tried many suggestions on this forum in the last week without success.
The following are the details of my issue and what I have tried to correct it:
Black Screen with Cursor only
Desktop is a Medion Akoya with Windows 7 Home Premium 64bit.
Ran Repair but told nothing to repair.
Tried restore point, still got black screen with cursor.
Tried Safe Mode, black screen with cursor.
Tried virus checking disk, found problems but still went to black screen after rebooting.
Cannot create a boot usb drive as I have an OEM desktop so no CD/DVD and unable to download iso file as Product Key does not work (OEM). Got another Win7 disc but did not work.
All files are present on the disk.
I want to retain data on my disk without doing a clean install.
Any help would be appreciated.

• Press one time CTRL+ALT+DEL
• Start Task Manager
• New > Task > Go to the Windows folder and click on explorer.exe
• Click on OK

Thanks for the suggestion georgeks. Unfortunately CTRL+ALT+DEL will not work on the Black Screen with Cursor.
Am I doing something incorrectly?

Try this: Re-boot your system, press F2 or F8 and using the down-arrow key select "Last Known Good Configuration", then press <ENTER>

Thanks again georgeks, I have tried all reboot options (safe mode, normal, last known good etc.) and they all lead back to the black screen with cursor.

Thanks 'ThrashZone'for the link. I have downloaded the file and copied it to USB but it did not work. I got the error below and am unable to correct it. Can you advise as to how I get around this please.

Can I clarify also that if I get it to download correctly, is it possible to reload Windows 7 and retain my files and apps/programs?

'Files copied successfully. However, we were unable to run bootsect to make the USB device bootable.'

Same issue here - tried all above suggestions - no change. Trying to run SFC /scannow but get message of a pending repair and to reboot, I reboot but still get same message. Tried another online suggestion to run: DISM.exe /image:d:\ /cleanup-image /revertpendingactions - this runs successfully and says to reboot, but even after reboot I still cannot run SFC and get same ..pending repair message - so I am stuck in this loop. I have also tries restore points which I can see but they won't run and get a message that system protection needs to be turned on.