Open task manager, click on the Processes tab & see if there's a LW process running. If there is, end the process. Did you uninstall LW via add/remove programs?

Otherwise, try the advice here to remove the files.
http://www.gnutellaforums.com/275825-post7.html
If you still can't delete the leftover LW files, try rebooting into safe mode & see if they'll delete.
Safe mode

As I said, I can only find info about an internal modem with that model number. What's the model of the other D-Link device...you never did say.

I use Firefox & it has no negative effect on LW but if you want to try going back to IE...go for it. See if there's any change.