I dowloaded houdini but for windows but cant see any prog ex..
can any one tell how to start it..ty

can you tell us what file you downloaded and from where?

here is a link to the windows installer file :
windows [vislab.usyd.edu.au]

Are you talking about the exe file that you can create a desktop shortcut with? I don't think there is one (at least I couldn't find it). You can start it by going to Start>Programs>Sidefx>Houdini on your windows Task Bar.

the exe's that run the programs are in the bin folder:
hmaster.exe
hhalo.exe
hselect.exe
hescape.exe