launching Lyx 1.6.5

[E. Kaplan]

I installed Lyx 1.6.5 on a Windows XP laptop, using the altinstaller 
(the only one I could find for Windows that had 1.6.5).  Before I 
installed it, I uninstalled the  previous version, 1.6.4.  When I try to 
launch Lyx, a DOS window flashes once or twice, and disappears.  Lyx 
never appears.
It shouldn't be THAT  tricky, should it?
Help, please!
EK