I cannot log in to FC5 as I get message that Disk is full.Now I want to access FC5 partition from Live UBUNTU CD to delete some files in FC5 to create space. Though I can mount windows partitions hda1 and hda5,I cannot mount hda7 Linux partition of FC5.I created a folder mnt/F to mount hda7.When tried to mount hda7 I get message as hda7 is already mounted or /mnt/F is busy.Please help.

My first guess would be that your liveCD found the partition and mounted it somewhere you weren't expecting. Check in /media as well as /mnt. If it isn't there try umounting it first:

umount /dev/hda7

you'll have to execute that with root permissions - either with su or sudo, whichever Ubuntuu Live has. Then, also as root, try remounting it.

mount -t ext3 /dev/hda7 /mnt/F

if your drive is not formatted as ext3 substitute what it is formatted for. (If you don't know the FC5 default is ext3)

Sometimes I would get errors such as that with mount or umount if I didn't have root permissions.

If all else fails, try umounting first with this command instead:

umount -f /dev/hda7

It doesnt work. Pl.see the output of command suggested by u.

root@ubuntu:/home/ubuntu # umount /dev/hda7
umount: /dev/hda7: not mounted
root@ubuntu:/home/ubuntu # mount -t ext3 /dev/hda7 /mnt/F
mount: /dev/hda7 already mounted or /mnt/F busy
root@ubuntu:/home/ubuntu # umount -f /dev/hda7
umount2: Invalid argument
umount: /dev/hda7: not mounted
root@ubuntu:/home/ubuntu # mount -t ext2 /dev/hda7 /mnt/F
mount: /dev/hda7 already mounted or /mnt/F busy
root@ubuntu:/home/ubuntu #

hmm, the only other thing I could think of is to ask where you are running the mount command from? I know you will get that error if you try to run mount from the mount point. Do you have a file manager looking at that directory? Perhaps that could have the same effect.

I also think that it is odd that umount says "Invalid Option". My umount recognizes the -f for "force". Hrmm.