I can think of two causes for long boot times.
1) starting unneeded services - like sendmail, apache or other things you don't need (something like sendmail, a mail server, takes AGES to start and it's only a very few people who actually need them, and it's easy to accidentally make Mandrake start these services during the install if you are messing about with it)
2) some service like the starting of your network is trying do something like mounting an NFS volume without having the portmapper started (I did that once - it took several minutes before it gave up, very annoying - but easy to fix)
I didn't quite understand however, is it just really realy long to start or does it actually hang and never reach the GUI ?
please reply back, thanks