Lost Registry? Win2K net

Well, not really lost, but our Win2K server running 50 stations drops the network every few weeks (sometimes twice in two days) and the log tells me it cannot find registry entries, so i reboot and all is well for a time, any suggestions please, arewe headed for a serious situation? We are waiting on a memory upgrade from fujitsu (we have 512 installed at present) could memory be an issue here?
Thanks in advance, JohnM