You may run into an issue where a dialog is open and is not displayed on your monitor. This issue seems to be more common in environments with multiple displays present. However, multiple displays are not a requirement for the issue to occur.
The following link contains information on how to bring the dialogs back to the screen:
http://communities.bentley.com/products/geospatial/desktop/w/geospatial_desktop__wiki/17093.data-browser-does-not-open-or-is-missing
An alternative to the suggestions in the link above, is to restore the defaults with a command line switch. To restore the default settings of your Bentley Map V8i installation, use the -restoredefaults command line switch as shown below. Additional information on the restore defaults command line switch, can be found here:
http://communities.bentley.com/communities/other_communities/askinga/w/askinga/quickly-restore-the-defaults-with-a-command-line-switch