If you have hosted School ERP Software on your local server and want to use in local LAN (Local Area Network) network then your School ERP Software hosting machine should have static ip address (not be dynamic assigned by your modem DHCP). Here suppose your server hosting machine have ip address 192.168.1.2 then when you are installing School ERP Software you should type 192.168.1.2/myschool/ not localhost/myschool/ in browser address bar otherwise you cannot access School ERP Software from other computers in your LAN and will redirect to localhost/myschool/ url.
If you have already installed School ERP Software using localhost/myschool/ then you can correct this by editing base_urlvalue in file /application/config/config.php . In this file change localhostto your hosting server static ip address like 192.168.1.2 .