Boot to black screen with cursor/Repair Windows

Hello.

Yesterday, when i booted into my windows 7 64bit installation it took me to a black screen with a cursor and nothing else.
What happened was i was trying to tweak the 'authui.dll' (i wanted to remove the logon picture...never do that again) and i changed a height and a width value. At reboot it took me to the black screen.
I booted into another windows install and changed back the files and restored every permission and ownership manually.
Then my original windows install (instead of booting normally this time) didn't manage to start. I have 'no gui boot' enabled. Instead of giving me 8 or so little blue lines on the top, it gives me the lines and a Bunch of other colorful dots horizontally. The colored dots change slowly and nothing happens.
In safe mode i see the same dots but Over the DLL loading screen.

I created a bootable usb drive that has the official windows installer on it and it is the same version as i use.
The installer console detects my original istallation, but i can't run sfc /scannow at all. (gives me the same error every time, screenshot below)

I also tried 'Upgrade'-ing but i could only do that if i were running the original installation.

Any help would be greatly appreciated. If i can't fix this installation in like 2 days i'm screwed

Bad news, Speedgamer pal !

You try SFC /SCANNOW : Run in Command Prompt at Boot to bring authui.dll in its place .

Later, if needed, you mar run Startup Repair .

Thank you Arc, I forgot to add that Startup Repair finds no errors
I will try sfc /scannow Method 2 right now. Wish me luck

speedgamer01 said:

Thank you Arc, I forgot to add that Startup Repair finds no errors
I will try sfc /scannow Method 2 right now. Wish me luck

Best wishes mate :)

Now i managed to run the sfc /scannow command with Brink's method, and it replaced my system files with the orginial ones... Although it said that it has done the job with errors (log:CBS.log) Attachment 202240

When i boot into the original installation it displays the windows logo (which it shouldn't i believe) and at the end it gives me a BSOD but no information under the usual text, no dump file and an instant reboot (i only managed to view the BSOD through my phone where i played back a video )

Sfc log attached.

To sum it up... Now i have all or most of the orginial system files (please, review my log file), but windows is unable to boot. I hope some guys see this, who could understand my log file.

IMO, SG pal, you should try Startup Repair now , for at least three separate times (with restarts in between every run) , to fix the MBR.

Thank you both seavixen, Arc. The only problem is that i would need to boot into my original installation (which i can not) to perform an Upgrade install or so called repair install.

speedgamer01 said:

I also tried 'Upgrade'-ing but i could only do that if i were running the original installation.

I ran the Startup Repair 2 times already, and it was doing the same: trying to fix disk errors for about an hour. It said the usual things, if it was successful windows will boot normally...

This problem is very misterious.
Also, i was using Intel SRT (ssd caching) (in the mode that stated that no data loss would occur if the ssd is detached)
My working installation is on the sdd which was previously used as a cache drive. I'm afraid that i did something real stupid.

Thank you for your efforts, I will do a clean install then I guess microsoft is not ready for such evil users like me trolling around in the system folders

This time I will install to the ssd. I think I will wipe it with my bootable installer to avoid the windows.old folder.

If anybody has any new ideas on this topic please feel free to post them here, my hard drive with the original installation will stay untouched for about a week.

Thanks again, have a nice day!