I had a number of problems installing SharePoint 3.0 Service Pack 1 and then Microsoft Office SharePoint Server 2007 Service Pack 1. In fact, I managed to put my server completely out of action and I have been trying to fix it off and on for a couple of weeks (I have been on holiday). This being my only day in for the rest of this year, I thought I should give it another go, as I did not want the server down for another week...
Well, I found a little called kb841216 that describes the problem:
"0x80040E14" or "HTTP 500" error message when you connect to your Windows SharePoint Services Web site after you install a Windows SharePoint Services service pack or a security update
The reason I get the errors is that the content databases are not at the same version as the application files causing an inability for SharePoint to read the database. You can solve this by running a nice little stsadm command:
cd /d %commonprogramfiles%\Microsoft Shared\Web Server Extensions\60\Bin
stsadm -o upgrade -forceupgrade
This may not fix your problems, but it sure fixed mine....
Now to get the Virus Protection problems solved....