Drive C Renamed Itself to F - Now What?

I installed a new Seagate 80G HD on Win XP. It looked good
at the time and was assigned F (Backup). When I rebooted,
the system "reassigned" the F (Backup) to C (Backup) and
made by C (bootable) the F drive. This is a big problem
because the boot partition and operating system are on the
F drive but many of the startup programs are expecting a C
drive location. The Disk Manager allowed me to rename the
C (Backup) to G (Backup) but when I then tried to reassign
the F to C (where it used to be) it said it is not
possible to reassign the boot drive. Obviously that is
not true because the operating system did it by itself
with no help from me. All I want to do is to reassign the
F back to C but I can't find a way to do it. Microsoft
won't help because it was an OEM computer so they say talk
to the OEM, but the OEM says they don't know how to fix it
either and Microsoft should help. I do have the lastest
bios so that is not the issue here.

Any ideas?

Caught in the middle,

Don