The problem with troubleshooting is that there could be a lot of reasons why something is not working. It's really a process of elimination until you end up with the real issue that 's causing the problem.
But here's the real eye-opener for me. Somewhere I read that all technology issues can be broken down into three main areas: connectivity, access and permissions.
Connectivity could be more a hardware issue than anything else. The main question being asked is "Can you connect to the services you are trying to access?". If it's a wireless network, can you connect? If it's a file on a server, "Can you connect?". Can you connect to the internet? Usually this is going to be a hardware problem. Either your wireless adapter isn't working or the router isn't working or some other piece of hardware has failed. If you can connect, for example, the little wireless icon in the status bar shows you connected and with full signal strength, then you can move to the next area.
The next question is "Do you have access?" You may be connecting, but you are not being allowed into the service. You may be able to connect to the file server, but you get an "Access denied" message. You attempt to log in to a site, but your password is rejected.
Usually this is a global issue, that is you can't get access to the device or the service at all. You're knocking on the door, but you can't get in. If, however, you get in you still have one more hurdle.
You might connect, and be allowed into the service but you can't access the file or web page. The message you normally get is "Permission denied". I have found that almost 90% of network issues boils down to permissions problems. Once permissions are set correctly, usually the problem goes away.
It's interesting to think that in the progression of issues, you are really moving away from hardware problems and more into software issues.
One more point. I have found that keeping a cool head in these matters makes for quicker resolution of the problems. Rather than yelling at tech support on the phone, and I've had more than my share of tech support people hang up on me, remaining calm allows you to state the issue you're having clearly and succinctly and