DVI is not working

[Abdul-Hadi Abulrub]

Dear all, 
 
After a good effort, I managed to have LyX installed on my Machine. It is
running XP. 
 
Unfortunately, when I tried to convert the LyX file to DVI, an error message
says that missing file called yap. I tried all possibilities even
re-installation but nothing works. 
 
It is set correctly set in preferences to use yap for DVI. 
 
Any help would be so much appreciated and many thanks in advance. 
 
Regards 
Hadi