Question : windows server 2008

I have a new Dell PowerEdge 2970 running server 2008 enterprise as a domain controller. For our small company ist a pretty sweet setup, Raid 5 (250GB x3) dual Opteron, 4G ram. We have about 130 users and this server runs AD, DNS, DHCP, and WINS. It is a file server for our shared drives. Every so often we have some serious network problems IE People not able to log in, not accessing their mapped drives, slow response when the drives do work etc. This is a new server less than 6mo old, running 08 and fully patched our network is 100M with servers all connecting to a Gigabit dell switch. When I reboot the server it comes back fine and people can log in again. When I look in my error logs all is well. I have almost no errors and everything appears to be good. Every test I run seems to be clean. any one have thoughts or comments?

Answer : windows server 2008

There is a known issue with windows 2008 and Endpoint 11 where network connections stop working, rebooting resolves the issue only for a short period and then it comes back again