Access is a multi user application.. it can talk happily to 15..30 users when using JET as its datastore, and thousands when talking to server datastores.. so getting you Access app to talk to two or more people shouldn't be a problem.
So first off
check that all people using the Access applciation are opening it in shared mode
I use 2002/XP and youneed to check the setting
tools | options | settings
look for the 'advanced' tab
and make sure default open mode is "shared", whilst you are at it set record locks to edited record (assuming you are using 2000 on).
do that for every computer that uses the application... Access settings apply to the local machine, not all computers using the application.
Next consider taking up startrekker suggestion and split the application into a backend (the data which sits on the central machine or server and handles all the data storage) and a front end (which contains all the forms, reports etc). consider deploying the front end to each individual workstation rather than on the server.. it will reduce network traffic, but it will increase the application support requirement. For 2..3 users I don't think you need to do this as a matter of urgency, but it is undoubtedly a good practise to get into. it can become a pain managing indivulaly deployed access front ends unless you use the right tools.
you may also want to think about tracking which user did what
you may also want to think about an audit log
you may also want to think about redesigning the application to use unbound forms... however with say 2..5 users Im not convinced you need to address that just yet if at all
Thank you so much for all the suggestions you have for me. will try to work on the issues we have, mostly the database is in use for query writing, there no apps in the database. trully, it was working fine, up until permissions been changed all over the network. me and another user lost our ability to work together. so we are trying to fix the issues. thank you.