Windows Server 2000 Problem

I have a Win200 Server with Symantec v10 and Veritas V8.6. On the 10th August it stopped allowing AV updates from the Security server and the backup jobs will schedule but not run. There also seems to be something blocking me from installing anything on that machine to do a scan.
Also it will not let me do any windows updates. Everything seemed to stop on the 9th Aug. Any suggestions or has anyone seen this before?