Domain infrastructure and transfer of roles knowledge required please

Hi All

Scenario

2x domain controllers both are server 08 R2

server 1 has the roles (handles dhcp and dns etc)

server 2 file server (handles dhcp and dns etc when first down)

server 1 has failed dead like cant restore theres something not quite right with the system state after a restore keeps booting to the recovery console. Have tried various means of reparing this but still reboots to recovery console. Have tried many backups and still same result.

Options please

As i understand it the two dc's replicate together should i

 seize the roles to server 2 (which is a good and working) if so then if we get server 1 up and going can i re-introduce it?? or what are the implications for adding another new build and transferring back to a new machine ?? is this the normal proccess after roles being seized.

I have heard i could produce a new build join it and promote it and let replication take place to update the info back to this new machine is this correct and if so do i use the same name as the original??? or something along those lines but ive never used this method indeed if it exist.

the two questions are simillar but different

thanks in advance

Jim