Setting cluster of PCs

[bhabani iitk ac in]

Dear All,
I have a 8 node linux cluster, each has hard disk.No node is isolated from world
I mean master home node has only one NIC.All are connected by a switch.
It was setup by one of my former labmate.Now he is not in our lab.

One of these node is file server for all users' home directory  as
/shared/home/users.In anotherone /shared/software is mounted for all nodes for
installing softwares so that all users from anynode access the softwares and
home directories.

Before some days,only that node which contained the auto mounted
/shared/software directory crashed.other nodes work fine only no user can access
that /shared/software directory.We can not recover our former operating
system(RedHat7.0).We install the new operating system(RedHat7.0).But I can not
make it as good as before so that it will work as before.As the maker of this
cluster is away now, I can not contact him.I have read something from
websites.But I can not find a solid idea.I learn that I have to modify some file
so that it will work as before.I will greatly appreciate if someone willl come
forward to help me in this regard so that I can let my cluster work fine as before.

with advance thanks,
Bhabani