Every system administrator encounters once in while in a problem where the solution seems to be a needle in haystack. My needle was an anti-virus version causing problems with my Exchange server.
I have an HP DL350 with Windows Server 2008 Standard Edition sp2 and Exchange 2007 sp2. The problem was that my Exchange server was freezing up once or twice a day.
I wasn't able to ping the server nor connect it via RDP, but the server was still powered on. The only way to get it back on track was to physically power it off and back on.
The log did not show any unusual error except from ILO error regarding the HP ilo2 network card. I applied the error to the HP support team for assistance. They sent me a driver for updating the ILO to a newer version, but it didn't work. The error was still there and the server was still freezing.
We started to examine the HP report and found some errors... The HP log showed up with ASR error that implies a motherboard error or driver error. So after a week with no success, they replaced the motherboard but it didn't solve the problem.
One of the suggestions was that it might be a misconfiguration of the network card. So we changed the offload setting of the network card and some HP errors were cleared, but the server was still freezing .
Another suggestion related to the anti-virus version on the server. I had ESET version 4 on the server, so I contacted the ESET support and they suggested to put an Exchange-related version of the anti-virus because it was an Exchange server. So I did it but it didn't do the trick.
So, for almost two weeks, the HP server division support tried to fix the problem. THey sent me patches for HP hardware and nothing seemed to help. We tried almost anything!
After some hard Googling, I came up with information that indicate that the anti-virus program is my "smoking gun." I turned to ESET again and, to my surprise, they said I should try a older version of Exchange server anti-virus software... and it worked!!!!!
In every problem you encounter there are always a few things that could be a prime reason for it. Don't take anything for granted. Explore, isolate the problem via a process of elimination. And, of course, search for solution on the Internet because there is always a chance someone, somewhere, has already encountered your problem or a similar one.
ESET and HP were very professional regarding my case and thier product and the support they give are some of the best in the business.