Failed Drive on a Raid5

Hello,
I am seeking assistance in restoring the files from what seems to be a failed RAID5 array. I am not a Linux expert. I am just good at following instructions. I inhereted this problem and need to resolve it. The system in question was running Red Hat Linux Interprise 4
1- The Raid had 4 drives. drive #3 Failed
2- The RAID did not self repair after replacing the failed drive as expected
3- The good drives were cloned and another attempt to repair the RAID through a windows interface failed or wasn't effective.
My questions are:
1- is it possible to Ubuntu online from a bootable USB to repair the Raid and restore the files/ Server?
2- If not, what are my options other than sending the drives out to a restoration company. I there a step by step guide to resolve such an issue? I can't imagine that I am the first problem of this kind.
Thank you in advance for taking the time to read this call for help.