You're right! going back to my original post
first of all thank you Bob, Kees and Mark for your help.
point is that switching to W8 from XP I feel my laptop (HP DV1310 us with 2GB RAM) works much better, everything (like bluetooth) works faster and smoother and I really like the OS (believe it or not, I should be among the few who like W8 starting with CP :-)).
on the other hand the new OS demands less resources than XP (such as RAM, tested from the System Monitor) and works faster with Office2007 which is my main tool (heavy Excel and eventually light Access usage). I don't see the point in using Ubuntu to run W8, since that setup will use more resources and it is not compatible with Office (am I right?).
as it has no driver for the graphics, I'm assuming there is some additional power not being used (please correct me if I'm wrong). at least for visual effects -not Aero-.
moreover, the laptop does not Sleep and the fun is continuously on (beyond the annoying sound, I assume the processor is overheated all the time, even when Sys Mon shows no activity) which makes me wonder about temperature risks.
thank you again, hope this will help you understand my concerns.
any help will be appreciated,