As the previous reply state, NTFS has no limit relative to currently
available disks (several 100s of Gig). However XP needs SP-1 and 48-bit LBA
enabled to handel more than 127-138 Gig (depending on how you define a Gig).
Further, your motherboard (or disk controller, if not on motherboard) must
be capable of supporting the drive size. Check with your motherboard maker,
or PC maker (if Dell, Gateway, etc) about BIOS-relatied size limits.
If the motherboard is an issue, and if no BIOS upgrade is available, try a
separate disk contorller on a PCI card. These are called ATA/100 adapters
for standard IDE disks) and SATA/150 adapters for the new serial ATA disks.