- click "run" in your start menu and type in "regedit". That should start the registry editor.
- if there are expanded branches in your first run, collapse them all and expand one called "HKEY_CLASSES_ROOT". First one from the top.
- find key called "drive" on the next level. Expand it and click on the "shell" sub-key. (pic no. 1)
The picture shows what your registry should look like. Note the status bar at the bottom says "My Computer\HKEY_CLASSES_ROOT\Drive\shell" - exact location of where you should look. Also note on the right side "default REG_SZ none". You can ignore REG_SZ part. Important thing there is that default - none. That is what it should read on your PC. Let's say that in my case the default value says "ACDBrowse", then the picture No. 3 shows what exactly would be activated ("C:\Program Files\ACD Systems\ACDSee\8.0.Pro\ACDSee8Pro.exe" "%1") on the double-click. ACDSee would start. Also, on the right click, first (bold text) item would be what the picture No 2 shows "Browse with ACDSee Pro" - user-friendly name of "ACDBrowse" sub-key.
The conclusion: In the "HKEY_CLASSES_ROOT\Drive\shell" key the default value should be "none". (as text, not empty)
One more thing:
DO NOT DELETE ANY KEYS!
ONLY CHANGE THE DEFAULT VALUE OF THE ABOVE KEY!
THERE IS NO UNDO FUNCTION IN REGISTRY EDITOR!