Firewire drive not seen by computer

Hello I have a problem with my external hard drive. I am using Win XP and
mostly do music recording with Nuendo. All the people I have talked to say
don't combine your internet use on a recording machine. Soooo...I installed
Win XP on a different drive (same machine) so I could access the internet.
Before on my recording drive, everything was working fine.....it would see
the external fire wire drive. Now after installing Win XP on the other
drive...neither sees the drive. Everything else seems to be working
normally. Before I could turn on my external drive and automatically the
computer would see it and display it. Now what happens is ... I hear the
little noise it makes when you disconnect hardware and when you connect
hardware, so I know the computer is seeing it but in My Computer no drive
shows........any help with this problem? Also is it possible for the
computer to see the firewire on both drives? Thanks....
Ira