Hope your uncle is using tally9.Tally is a simple package so dont need a higher configuration.Since only 5 users are there,u can go for a an IBM X3200M3,4 Gbram,250Gbx2 HDD and raid1.HP ML110 G6 servers also do the job.Both had onboard Raid0/1 controller.If RPS needed then you must get atleast...