Multi-user

I'd installed SambaPOS3 and followed the steps to use the multiple user service with SQL Express 2012 but in the 4th step when I clicked on Start client now, it showed me the firewall message and I

WinXP add Multi-user patch on I3-2350M @ 4G RAM，5 users by 2x client，every user is very slowly，How to improve the performance and speed of response？It can improve the performance by using Win 2008