Welcome to LQ! I haven't been here for a while myself, but I'll try to help you.
First make sure that you don't have anything that you want to keep on partition 5 or 6. Any data there will be destroyed by following this procedure!
If the partitions are mounted, they need to be unmounted now:
> umount /dev/hda5
> umount /dev/hda6
Then enter fdisk:
> /sbin/fdisk /dev/hda
'm' will print a help menu for you.
Use the command 'd' to delete partitions 5 and 6, then use 'n' to add a new partition. Since you want the new partition to fill up the disk, just use the default values for first and last cylinders. 'w' will write the partition to disk and exit fdisk. (You can chicken out with 'q')
> /sbin/mkfs.ext3 /dev/hda5
to create a file system on your new partition.
Make an empty directory
> mkdir /hikito
Only the partition table left and we're done! Open /etc/fstab in a suitable text editor (emacs is always
a suitable text editor, by the way
). Comment out the lines for the removed partitions. This is done by adding a '#' character at the beginning of the lines. Add this line:
/dev/hda5 /hikito ext3 defaults 1 2
Save the file, reboot and enjoy.
Hope I didn't forget anything. Good luck!