My PC wiz/programmer/repairer friend has a 2 yr old HP notebook with
factory installed Vista premium 32 2GB which he upgraded to Ultimate 32
with 3GB. Then he installed W98, XP Home and XP Pro to be able to
service customers with different OS. That means his notebook has 4 OS.

And because my Vista premium 64 does not support FAX (I am not happy
about this....it's a backward step since both my 2000 W98 and 2005 XP
notebooks carried FAX, now replaced by FAX-less VISTA Premium. Oy!), he
installed XP Pro to enable FAX thru some kind of (?) virtual PC
download. For a while (3 days) I had two OS in one PC. I eventually
deleted XP because of tolerable minor (but disconcerting)
incompatibilities with 64 bit. I think so far, VISTA 32 bit is more
flexible.

In summary, done by advanced PC techie, a notebook can have more than
three OS (according to him, as many as he wants).


--
coolnewyorker