Black desktop, no icons, no taskbar even after windows reinstall

Desperate situation here...

I have WIN7 SP1.
After logon the desktop is black with no icons. There is no taskbar, no start button. The shortcuts WIN+R, WIN+E, WIN+F, etc are not working.
The problem is also there in safe mode.

I read many things about explorer.exe being corrupted or infected.
My C:\Windows\explorer.exe file is 2,616,320 bytes

I tried many suggestions:
-I made sure there are no multiple displays in Display settings.
-I updated and run Malwarebytes Anti-Malware.
-I did a system restore.
-I run SFC /SCANNOW and took "Windows Resource Protection found corrupt files but was unable to fix some of them", but in the log file (CBS.Log) I found only errors "Cannot repair member file" about wmp.dll of Windows Media Player, so I did nothing cause Windows Media Player is irrelevant.
-I even did a windows reinstall, but the problem is still there! (btw, since then, windows fails to install many updates including IE11, so I now have IE8)
-I deleted the "iexplorer.exe" in key "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution options" (there was no "explorer.exe" key to delete).
-I made sure the value in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell is “Explorer.exe”.
-I did a Quick Scan with a Windows Defender Offline cd and found nothing.
-I created a new Windows user.

Nothing worked.
I cannot work on my pc and I am really desperate.

Thanks for your help.

I followed this crazy suggestion from Windows 7 - There are No Icons or Taskbar on my Desktop
HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Windows NT > Current Version > Winlogon > Shell (other window) > delete: explorer.exe and retype it in
(retype it??? why???)

I now have a taskbar and desktop icons.
(although I should wait, because the user that provided that solution had the problem reappear after 2 days)