Here are some registry keys for explorer shell extensions that we find extremely helpful. Just cut and paste the text into a file and name it "something.reg" and you will be able to double-click it to import it into the registry. 

"Edit with Notepad" right-click option - no more "Open With"

cut from here >>>

REGEDIT4

[HKEY_CLASSES_ROOT\*\shell\Edit with Notepad\command]
@ = "notepad.exe %1"

<<< to here

"Command Prompt Here" right-click option - opens a command prompt at the selected directory

cut from here >>>

REGEDIT4
 
[HKEY_CLASSES_ROOT\*\shell\Command Prompt Here\command]
@ = "cmd"

[HKEY_CLASSES_ROOT\Directory\shell\Command Prompt Here\command]
@ = "cmd.exe /k cd %1"

<<< to here

"Register/Unregister DLL" right-click option - very handy

cut from here >>>

REGEDIT4
 
[HKEY_CLASSES_ROOT\dllfile\shell\RegDLL]
@="Re&gister DLL"
 
[HKEY_CLASSES_ROOT\dllfile\shell\RegDLL\command]
@="regsvr32 %1"
 
[HKEY_CLASSES_ROOT\dllfile\shell\UnregDLL]
@="&Unregister DLL"
 
[HKEY_CLASSES_ROOT\dllfile\shell\UnregDLL\command]
@="regsvr32 /u %1"
 
<<< to here

Enjoy!