I have an HP DV1150US, and just bought a Toshiba M305D, 64 bit dual core AMD laptop with Vista. You are actually "Downgrading" by going to Vista, your DV machine doesn't have the CPU power or memory (unless you spent several hundred dollars to bump up the RAM). If you bought the software with a credit card, return it (they will say you can't, but make them "receive" it ) as defective (Vista is defective as it doesn't support tons of things that work in XP, there is no legitimate technical reason for this) and then arbitrate with your credit card company to get the charge for the software refunded. If everyone did this, then MicroSoft would not produce such incompatible software. The public has had the wool pulled over their eyes ... if you bought a toaster, and it made beautiful toast 39 out of 40 times ... and in 1 out of 40 times, the bread came out on fire ... you'd return it right? Vista'=flaming bread about 3% of the time.
I have used literally dozens of OS in 30 years as a software professional, and I can say with confidence, that your problems with Vista are just beginning. You may be happy with Vista and the tens upon tens of hours it takes to get productive again IF and only IF you are a serious Microsoft zealot.
Look at what millions of other users say about moving from XP to Vista. Microsoft has a policy for Corporate customers only, that if they buy an Vista machine, they have rights to change (really upgrade) to XP for free (look it up).
If you stick with Vista, you are on a never ending MicroSoft treadmill to buy new hardware that works with your new OS, then be forced into another new operating system (MS will drop support for Vista and force you to Windows 7 faster than a hot potato) when they refuse to support Vista read:http://en.wikipedia.org/wiki/Windows_7.
If you stick with Vista and have any significant investment in prior software ... you are going to have to replace a portion of it. My 4 year old $600 Office XP Pro package for one ... doesn't work on Vista!!!
If you have to have Vista, you can resurrect your XP OS and install Sun's FREE VirtualBox and run Vista as a "Guest Operating System" within XP !!! Then you can "play" with Vista to your hearts content, and when you really need something to work (read: your hardware or your existing software), you can use the native XP. Oh yeah ... you are going to need a new machine to do this, but you would need that for Vista anyway. For $700 at BestBuy, you can get a Toshiba M305D with 2 Core 64 Bit AMD CPU, 4GB Ram and Vista Premium aldeady installed 160GB or so drive ... much less that it would cost you to upgrade your DV1000 for just the RAM and Drive.
Programmer / Power user - 30 years experience