Vista - File Open and File Save As Dialog Freeze and Hang All Applications

Dear Colleagues,

Whenever I request a "File|Open" or "File|Save" from any application, the
mini-Windows-Explorer dialog box that opens freezes and hangs the entire
application. The dialog box is not populated with the existing files in the
default directory, the column headers are blank, and the dropdown arrows
adjacent to the column headers are distorted. This failure of "File|Open" and
"File|Save" occurs in all Office 2003 and Office 2007 applications, in MS
Outlook 2007, in Adobe Acrobat 7 Professional, and other applications. I can
only open MS Office or PDF files by double-clicking the filename in a
full-Windows-Explorer file listing. Perhaps the mini-Windows-Explorer
subroutine is corrupt. Any way to restore it? Cntrl-S still works for saving
existing files. I am logged on as an administrator.

Thanks very much!

Lightfoote
Dell Opliplex GX 280 RAM 2 Gb DDR 533 SATA 80 Gb 3.2 MHz Processor ATI
FireMV2200PCIe with video RAM 128 Mb; Rating = 3 (!)