I have a default layout of SL 5.1 on my first harddisk and performed a
default install of Fedora 9 on a second disk last night. I am now
having problems booting SL 5.1 which seems to be related to the LVM
setup on the Fedora disk (which uses the same names as SL 5.1) taking
preference over the LVM setup on the SL 5.1 disk. In particular, when
grub tries to boot SL with something like:

title Scientific Linux SL (2.6.18-53.1.14.el5)
        root (hd0,1)
        kernel /vmlinuz-2.6.18-53.1.14.el5 ro
root=/dev/VolGroup00/LogVol00 rhgb quiet
        initrd /initrd-2.6.18-53.1.14.el5.img

it gets the right kernel but the root from the Fedora disk and not the SL disk.

The SL installation is my main one and Fedora is only being installed
for a small project which requires recent kernels. I know very little
about LVMs, am happy to perform possibly unsuccessful experiments on
the Fedora disk but do not want to risk the data on the SL disk.

Can I resurrect the LVM setup on the SL disk? And then, perhaps, add
the information on the Fedora disk into it or, if possible, have two
separate volume groups with different names if this is the root of the
problem. Many thanks for any suggestions.