How can i share user programs and files in my domain environment?

i had this computer which ran XP SP 2 & SQL 2000 with loads of sensitive stuff innit, @ a tym was running as a server until it became inaccessible to other computers in our group then tryin to make it accessible on time was hopeless so i decided install a brand new server with 10 TB which is now running windows server 2008 R2 & SQL 2008 but i still want to use that old server in my new domain as a client and use those old programs and files instead or purchasing a new package and transferring tones of files to my new server! i made it as a power user and domain controller then i tried to share it to everyone but i still cant see shared files from domain or clients..