I have searched through forums, but could not find the solution to my problem:
I have a notebook ASUS with Windows 8 preinstalled.
Yesterday I was doing some housecleaning jobs with some freeware tool (don't remember the name).
Afterwards I have not been able to boot into Windows.
CURRENT SITUATION: When I switch the PC on, after the welcome screen of ASUS and Windows 8 the system goes to a blank screen (no cursor, no mouse, CTRL+ALT+DEL not working) and hangs.
On next reboot, it does not start automatically the Recovery/Repair procedure and goes through the same steps again. It's not a loop, it just hangs.
Looking into c:\windows\system32\LogFiles\Srt\srttrail.txt I see the following error message at the bottom of the file on the time of my last boot attempt: "Operating system version is incompatible with Startup Repair"

I tried several things without success, so now I want to solve the problems one by one and first thing is to understand what might be causing the "Operating system version is incompatible with Startup Repair" error and how it can be solved.