In my Experience, Cubase shall not be installed on a diffrent Partition on your system than the one where you have your OS. I have tried so many diffrent versions of this install, that I am pretty darn 99% that it will always fuck up if you install it in another partition. Keep ONE partition for only: OS, Cubase, VST's and their Sound banks. Keep ONE for Audio and Samples.
Please also do consider setting your PC up the correct way, by following one of the best MUSIC XP tutorials I have ever seen: www.musicxp.net . I can not say how much that has helped me in the past.
of course there will be people disagreeing with me, but you can all just bugger off, i know more than thou! (at least about pc structures and xp)
it all depends if I am running heavy plugins or not, if I am running medium heavy ones, I can run around 32 with fx and maybe 16 audio tracks. I have a 2.4ghz x2 amd with 2gb ram.