This is a recent problem; I have 5 PC's on a home network and two PC's (desktop and laptop) that now have the following problem.
To connect to an unmapped network drive, I would typically click Start > Run then type \\computer name\drive letter. This would bring up the unmapped network drive. Now it opens the "open with" dialogue window. Connecting to mapped drives can still be done either via the file managers or address bars as expected. New drives can be mapped. The problem is an annoyance when using the laptop to connect to other PC's not on my home network. Any suggestions?