1. Load the default linux and on terminal login as su.
2. mkdir /mnt/pcq
3. gvim /etc/fstab
4. Now make a mount point for the PCQ linux usind the hdx it was installed,
Save the file.
5. Then mount it. by issuing mount /mnt/pcq
6.Now issue gvim /mnt/pcq/boot/grub/grub.conf (or menu.lst)
7. Check the boot parameters for the PCQ linux with the one that you have posted(ONLY PCQ entry). If they and the above posted differ, copy the entry to above grub.conf, replacing the old PCQ boot entry or just make the necessary changes.
This generally happens when other distro change the boot parameters of the distro installed before them. I suspect it might have changed the mount point entry.
Be careful not to mess up, otherwise you will have to use bootdisk rescue