Generally these aren't a big deal to bring up on another DC. Especially if your DNS is AD integrated.
So the server is DNS / DHCP / Print Server / Etc.
presumably you have all this data safely backed up.
Plus is houses all user folders / profiles / network shares.
This is windows attempting to stop data corruption propagating to your other DC.
At the moment windows has stoped the server from replicating with DC02. The main issues now are the Event ID: 474 NTDS ISAM / Event ID: 1084 NTDS ISAM.
Because AD is corrupt on the server.
AD on DC01 can be accessed now and all data seems to be there except I get errors when trying to access an OU which houses all the IT suite computers.
Yes, but you'll need to do an authoritative restore from your second dc.
I am hoping now that this issue is being caused by the faulty hard drive and that "IF" i can image the old / new disks then AD will replicate again. Clutching at straws I know.