How to make Windows 7 get working again (black screen with a cursor)?

g1o2r3a4z5d6 said:

I tried to change the registry values (via cmd on Recovery CD).

HKEY_LOCAL_MACHINE\Software\Microsoft\WindowsNT\CurrentVersion\Winlogon

shell was: cmd.exe /k start cmd.exe
userinit was: X:\windows\system32\userinit.exe,

But if I change it back to explorer.exe and replace X with C then restart, still get black screen.
Then go back to look at Recovery CD and type regedit in cmd and seems like registry didn't save my corrections.

What to do now?

You don't know what you're doing!! You were booted form recovery CD to some mini win7. The commands affected the mini win7 (in ramdisk, so destroyed anyway later). You have to change the rela win7 on partition labeled OS.

Problems began after changing the registry permissions? That was all you did initially?

g1o2r3a4z5d6 said:

Yes, I want to know why regedit won't save my changes.

Because you change the registry of winpe (mini win7 for recovery).

Why did you think the bootmenu (BCD) was faulty... it DID start and does still start win7!
Why messing around with partitions?
Why did you reset file permissions to default? They were not wrong... =>resetting to default doesn't hurt.

Because on the other forum they told me it's the problem. And Windows 7 on my PC doesn't start.
Because I wanted to get my Windows 7 working back as it was perviously.
They were wrong because I changed them by mistake.

In recovery environment select "system restore". Go back in time prior to date/time when problems started.
System Restore

All exe, dll, registry and other windows files will be rolled back to that time. Data files like WORD and excel documents are untouched.

In first post you say: "Safe mode, last known good configuration and system restore all don't work."
What error message when doing "system restore"? Restore points are listed?