Hugh Wyn Griffith

You could try installing the free VISTABOOTPro and see if it enables
you to see and choose from your three OS's

I've read that if you have two OS installed and install VISTA to "dual
boot" it lumps the two or more earlier OS's under Other Windows and has
an entry for itself. That if you click on Other Windows you then get
the choice you had before you installed VISTA.

I don't know if this is true or not but VISTABOOTPro might sort out
your multiple OS's if the way you installed VISTA did not destroy them.

Others have explained about the change in the boot files with VISTA and
that you can edit BCD but I gather this is tedious == VISTBOOTPro puts
a GUI front end on this and I found it s m o o t h .....

Google on [VISTABOOTPro] and you'll find it easily enough.