Commonly,vista DVD contain most computer's driver,and if not it will search automatically in the windows update
I dont recommend you to update if your ram is less then 1G.
There is no reason not to get vista if you have at least 1gig of ram. A lot of these so called horror stories that you hear are from people that have no idea what they are doing. I have been running vista since november when it came out on our msdn account and i have had absolutely no problems what so ever with it at all!
yes, i ran vista on all my pc's since rc1 (5600...i believe)... and only trouble i had was getting my dell printer to go.. which they released a driver for this month .... other than that.. not problems... i love the new look and new features... especially ready boost..... i run it with 1gb and have no troubles at all... even find ready boost gives me more fps in games... i would go for it if your computer is good... good luck