[Solved]- Starting /dev/disk/by-uuid/ad5290fc-d073-45db-bfaf-86f25f401a07 [1;31maborted [0m because a dependency failed.

If you got any error like this at f15 booting time:
Starting /dev/disk/by-uuid/ad5290fc-d073-45db-bfaf-86f25f401a07 [1;31maborted [0m because a dependency failed.
Case I:
First check your /etc/fstab,
if you got any line starting with
UUID=ad5290fc-d073-45db-bfaf-86f25f401a07
Note: In my case UUID=ad5290fc-d073-45db-bfaf-86f25f401a07. But in case UUID will be something else.

Reason:
Reason for this failed message can be due to change in the partition like partition recreated after delete or filesystem type change (say ext3 to ext4).

Solution:
If it is due to change in partition you can use any one of the two methods:
1. Use blkid to find the UUID of /dev/sda5 (say the partition which has been changed is /dev/sda5)
# blkid
copy the UUID value from the output of the above command for /dev/sda5 only and paste it in place of previous UUID in /etc/fstab

Note: If the changed partition is your root partition you must have to edit /etc/grub.conf file
root=UUID=^new UUID^

2. open /etc/fstab file as root.
Now, edit only first field.
for example:
if it is like:
UUID=ad5290fc-d073-45db-bfaf-86f25f401a07 swap swap defaults 0 0
Replace the first field with partition name /dev/sda5 (say the partition which has been changed is /dev/sda5)
/dev/sda5 swap swap defaults 0 0
Note: If the changed partition is your root partition you must have to edit /etc/grub.conf file
root=/dev/sda5 (say the partition which has been changed is /dev/sda5)