Hardy/Ustudio/64Studio Multiboot - Advice on removing XP

Hi everyone, I'm very happily converted to Linux and have a multiboot system with Ubuntu Hardy for home tasks, / Ubuntu Studio 8.04-rt for my hobby music composition / and Win XP I now want to remove XP and replace it with the 32-bit edition of 64Studio to try that out in comparison to Ubuntu Studio. I plan to order new hardware this wek ( AMD X2 7750 64bit CPU and new mobo ) to set up 64Studio in 64-bit as my main system running Ardour, Rosegarden, Hydrogen and Linuxsampler. But , on the existing 32 bit machine I want to make sure my Hardy and UStudio installs stay intact, but use the win partition for 64Studio. I have quite a few Ardour sessions in Ustudio that I dont want to lose. I have the iso DVD ready to install 64 Studio I'm guessing it will ask me for a target partition to install , and I'm hoping that when its complete i will be able to see Hardy/Ustudio and 64Studio as the 3 boot choices in Grub. i THINK i have Grub installed already as part of the Ubuntu installs. At the moment , when i boot i get black screen , with my boot choices ( and i see some words about Grub flash by just before hand. ) Assuming I do have Grub installed, and I'm not relying on Windows MBR will i be OK just to install 64 STudio over the existing XP partition ? How can i check the Grub install ? The win partition is 90Gig - so lots of available space. Anything special about swap partitions etc ? Any thoughts/help on this multi-boot set up ? Cheers Pete