Two ways you could regain the access to your network drive.
1- Browse through "My Network Places" and after finding the network drive, right click on the computer and "Map" it as "K" drive.
or
2- Go to start / type in CMD and click on Enter -> in DOS prompt type in
net use K: \\name_of_the_computer_you want_to_access\folder name and of course you will need the correct user name and password to map to remote computer.
Cheers