Windows 7 black screen with moving cursor

1) When you switch ON your computer, start tapping the "F8" key to get 

2) Select "Safe Mode with Networking" 

3) Click on Start --> Run --> Type regedt32 and press Enter. 

Registry Editor will be opened. Navigate to the following location 

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon 

At the right side, find the strings shell & userinit and check the following 

shell value data should be 
Explorer.exe 

userinit value data should be 
C:\WINDOWS\system32\userinit.exe, 

If shell and userinit are having different data values then change it as mentioned 

above. 

Just double click shell and userinit and enter the data values as 

shell --> "Value data" should be 
Explorer.exe 

userinit --> "Value data" should be 
C:\WINDOWS\system32\userinit.exe, 

Note: there is "," at the end of userinit.exe 

Then download "Malwarebytes' Anti-Malware" 

Update it and perform "Full Scan"