May 22nd, 2015, 01:33
I'm not familiar with the term "GRUB". But to answer your other question, you would do better to re-partition your current system drive and add a new 100GB D: drive there for installing XP. With Windows OS's, pre-Win7 platforms should always be on the primary drive. Is their native environment. The extra drive can then be reserved for moving your sims and games to for protection against system viral infections and system drive failures, or it can be deployed as an additional storage drive.
The only problems i can foresee is that with dual booting Windows systems, the most recently installed OS becomes the default primary system. So XP will become the default automatically during the boot sequence and you'll have to standby to manually select Win7 during the boot process....