While I do some support stuff as well sometimes I was really interested in how MS do troubleshooting in SharePoint in their support team. Russ White is the guy who gives insight details on how MS deals with all the calls they get. I know what information you need to give MS if you submit a call but it was really nice to see how do they identify the problem using the 5 "W"s.
Besides getting those W's right, they also define the scope of the problem. When they have all the information they contact the person who issued the problem and asks if this information is correct, and from there on they are going to try to solve the problem.
As a matter of fact I do use those terms as well while I'm troubleshooting the calls I get from 2nd line support and quite so often you can solve the problems without doing any drastic changes or any change at all. Most problems or issues are resolved really quickly by just giving some good thought about what the user is doing.
When they do problem solving they are going to research the following logs :
- ULS logs (~12\Logs folder)
- IIS log files
- Event viewer
Besides doing the logs they also use some monitoring tools like Netmon.. although WireShark is more recommened and more easy to use.