My Remote Desktop stopped working -- how to fix?

I've used Remote Desktop to connect to my work machine for years.  As of two days ago, it stopped working.  To be more specific, when I try to connect to it now, I click the "Connect" button, and then nothing happens.  No error message.  No "failure to connect."  It just doesn't do anything.

Some relevant facts:
- This is all on our work network (both via VPN and when I'm in the office)
- I can remote desktop successfully to many other machines in the office
- I did just recently install LogMeIn on the computer, but it did work after that for a few days.
- I have LogMeIn disabled at this point, just to be sure, though.
- I did just install XP SP3, but it worked after that for awhile.

My problem is I can't think of how to debug this.  There is nothing in the event logs.  There seems to be no verbose or debug mode for mstsc.exe.  I'm stuck.

Any ideas?

Thanks,
-DaveStart Free Trial