Search Companion Starts If You Double-Click a Folder or Drive

Click Start, Run and type this command:

regsvr32 /i shell32.dll

or
Manual registry fix

To fix the problem manually, open Registry Editor and navigate to:

HKEY_CLASSES_ROOT \ Directory \ shell

-and-

HKEY_CLASSES_ROOT \ Drive \ shell

In the right-pane, locate and click the (Default) value
Click Modify on the Edit menu
Type the word none in the Value data box, and then click OK
Exit Registry Editor.