Windows 7: File browser dialog not showing in some apps

Hi, hope someone can help. I have a strange problem in Windows 7 Ultimate 64 (SP1). I have had this problem before and I ended up having to do a clean install to fix it so I am hoping I can find a solution.

The problem is in some applications (e.g. Firefox) when I click an option to open a file open or save dialog box the dialog box just doesn't appear.

There is no error and the application does not crash the dialog just doesn't appear. No error is logged in the system event logs either.

I kn ow this isn't a problem with Firefox specifically because it happens in other applications too such as Winzip 14 and NERO burning ROM.

Applications that use the newer style interface such as Office 2010 seem unaffected.

Does anyone have any ideas of what I can try? I really don't want to reinstall Windows only for this to happen again in a few months



Any help appreciated.

Brian