Dual-Boot with w’98 and w’2000

I have a computer with two partitions, primary with 2 gigs with 98 in it, and i want to install w’2000 in the other partition, with 12 gigs.
When i try to install w’2000 (no update), the installation process goes fine until the first reboot, then the machine hangs with this fatal error “INACCESIBLE_BOOT_DEVICE”
The system is a PIII with 128 megs of RAM.