When Vista starts behaving strangely, as if some system features are missing or broken, one of the standard ways to fix this is using the System File Checker (sfc) command. There are two ways to run this command: (1) from an elevated command prompt inside Vista, or (2) booting from a Vista DVD. Elevated command prompt: Enter "cmd" in the start area, and press Ctrl-Shift-Enter. This will open a command window with elevated (i.e., Administrator) rights. Enter the command "sfc /scannow" (without the quotes). Booting from Vista DVD: Insert your Vista DVD in the drive and boot from it. Select Repair my computer -> Next -> Command Prompt Enter the command below: [presuming c: is your Vista drive] sfc /scannow /offbootdir=c:\ /offwindir=c:\windows\ Note: There are instances in which the first way of doing this will fail but the second way succeeds. So, if the inside Vista version fails, try the second approach.