I had a Bug with Greasemonkey / Firefox on my Vista. Its scripts don't work and stuck on install window.
Here is how to fix it:
Go to your Firefox Profile:
C:\users\[User Name]\AppData\Roaming\Mozilla\Firefox\Profiles\
(You need to change your folder view settings to see this folder. Go to, "Tools -> Folder Options -> View -> Hidden Files and Folders" then select "Show Hidden Files and Folders. )
In your profile folder first create a new folder and name it "gm_scripts" (without quotes). Then create an empty text file and rename it to "config.xml" (without quotes).
- note: if you are using portable Firefox your profile folder is here:
...\FirefoxPortable\Data\profile
