Hi Rajiv,
On the old machine which has the connection information, find the following file and move it over to your new machine:
C:\Users\[myUserId]\AppData\Roaming\Neolane\NL_5\nlclient_cnx.xml
Note: If you'd like to bring over your locally cached info for each connection as well, you can bring along all the other XML you see in these directories, too. (You'll probably want to zip the whole directory in this case because this can be a lot of data.) This is optional.
Using regEdit, find the entries resembling NL_5 and NL_6 below and export each of them:

These registry entries contain encrypted passwords for your connections defined above.
Bring the exported keys over to the new machine and use regEdit to import them there.
Lastly, you can open your Adobe Campaign client and confirm that your connections have been brought over along with the corresponding usernames and passwords.
Thanks,
David