I cannot get my "Open..." (ctrl+o) dialog box to show up when i have an drawing already open.  The command line shows the function being active but nothing happens.  I can get it to show up if i close out of all active drawings.I can still use windows explorer to open multiple projects but it is very inconvenient.  Normally i would just reset my computer back a week using system restore, but the company network went down last week and i don't want to lose the change in registry files.Any help would be grateful.

You may have your dialog "off-screen". Try to increase your Windows resolution or press Alt+Shift+space, down-arrow and try to "hunt" your dialog back to screen with the arrow keys.

Thank you for the quick response Vladimir but it does not appear that dialog box is offscreen.Its almost like the command line is a dead link while there is a drawing already open.  Normally if i have the "open" dialog box active i can alt+tab and see AutoCAD say "select file".  In this case, as soon as there is a drawing open I can use any command line to open a file and command line shows at the bottom of the screen but nothing happens.After looking more into this I see that the "new" command line does not work as well.  Unless once again, all drawings are closed out of AutoCAD.

okay, its fixed for the time being...I don't know what happened but I was trying to see if the same issue would occur in project manager.  I opened a project and the browser worked fine.  When i was showing the issue to a co-worker my "open" dialog box is working again.

Maybe Windows had not enough resources (memory) to open another window (dialog).

[QUOTE=jcastle]okay, its fixed for the time being...I don't know what happened but I was trying to see if the same issue would occur in project manager.  I opened a project and the browser worked fine.  When i was showing the issue to a co-worker my "open" dialog box is working again.[/QUOTE]
Check SDI Mode:

I have the same issue has anyone found the how to solve this problem?

easy one:
type in "filedia" and set to "1"
if set to "0" the dialog box will not open.

Hopefuly it will help next time ...

Yes this worked!!  Thanks