|This problem can be caused by ‘malware’ but check this registry key before running your ‘anti‘ programs. |
Firstly, start Explorer via Task Manager by pressing Ctrl+Shift+Esc then on the Applications Tab click ‘New Task’ at the bottom, type explorer.exe and press Enter. If it doesn’t start, you are almost certainly infected.
Check the registry key by going to Start > Run, type regedit and press Enter. In the left pane navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon. In the right pane, make sure there is a REG_SZ named Shell and it has a value of "explorer.exe" (no quotation marks). If it’s not there, create it by clicking Edit > New > String Value then right-click it and type explorer.exe then restart the computer.