Forum and ASP pages stop working.

Check the Microsoft MSDN site to see if that lets you know whats wrong with your server.

Also try uninstalling and reinstalling IIS and see if that clears things up.

I had a similar problem, and the solution lied on the IIS application pools.

My advice to you is to create a new app pool based on the default one and change settings according to your needs, my suggestion would be to read a bit about app pools and configuring it then set your own customized app pool for your web site, taking into account server memory and other factors.

Also check: I was surprised that when I installed my WinSrv2k3 it was giving foreground processes priority over memory, and a server runs mainly background services, so after I change that and got a proper app pool configured in IIS, my web sites have been running for months and months on end without the slightest problem.

App pools are not one size fits all, which means it has to be adjusted in accordance with your server specifications, and web site requirements, but so we can test, tell me about the server (CPU, memory, how many web sites, what services do you run on the box, if you run performance counters on the server how much CPU utilization there is on average per 24h) all this impacts on how you configure your app pools.