I've got a Windows Server 2003 box with IIS 6 installed. There is only one ASP-powered website running on this server. Approximately every 1-3 hours, IIS stops responding (returns 500 Service unavailable) for no good reason. There is not high server usage, no logged errors, nothing at all.
Restarting the IIS (really only the service) fixes the problem until it happens again.
I don't know what to check anymore. Has anyone of you had similar problems?