Win Nt4.0 Dos DB running slower &slower

We recently switched from a Netware 3.12 platform to Nt 4.0 platform. We have Win9x clients and were runnning Foxpro 2.5 dos programs. They ran fine under Netware, but now on NT they runs very slow and continue to slow done. The programs will also do strange things like close out for no reason or lock up. Any info would be greatly appreciated. Also this server needs to run 24/7 so rebooting now and then(once a week) isn’t really a good option. Thanks