SERVER CRAWLING

HI

Urgent help needed
My server’s crawling. Its a Quad Core 1.8 with 2 Gb Ram. Its acting as a DNS server.
First i thought its to do with Symantec end point protection. I ended its service but still no major luck. At some point I cannt even login to server.

CPU usage is between 20% to 50%.
I looked at the processes and the only major ones are smcsrv.exe which is 101 Mb and services.exe which is 144 Mb

Urgent help needed.

Thanks