What's "file picker" ?

I will assume that you are talking about the window pop-up that occurs when you hit "Attach" in your mailer.

1. Try TweakUI to repair the program-icon shortcut relationship.
2. Be sure the registry is in order
3. Defrag and scan disk to be sure all is in order there
4. run sfc /scannow to be sure all of Windows working files are there and in order
5. Be sure your browser has not, internally, been set up to use only certain search modes, or certain saving processes
6. I have three programs set up in my start folder to be ready to go when I finally sit down to work...they run continuously: a] WinPatrol, b] Process Explorer, and c] MacDev's STOPIT... at least one of these three will kill the program that has tied your system in knots...that is, if the Taskbar is operable.
6. Completely uninstall your browser, don't forget the c:\Program Files\Common Files\references to that browser...then reinstall it
7. Repeat, but this time be sure not one reference to the prog is to be found in the User or Machine keys in the registry.
8. Return to the Control Panel...uninstall all Windows addon options, then regclean, then reinstall all options
9. Visit Control Panel...track down "Services" and check which are disabled, and have some inference to a possible cause of the problem...turn it back on While you are there, go down to Messenger, and disable it.
10. Go to inboard Help Centre

etc.