As basic as it sounds, restarting your computer can resolve many problems. Try it before you change anything.
Whatever is going on, document it carefully. Write down any the exact text of any error messages, as well as exactly what you were doing when the error occurred. It’s very difficult to help someone who simply says, “It won’t work” or even “Word keeps crashing.” The more information you can gather or provide, the more easily it can be fixed. If Word crashes every time you try to access a document on the LAN, that’s important information. The problem could be with with your network access, not with Word. When anything crashes on a Windows system, you will usually see a dialog box that has a little “More” button — hit it and write down the information (I know, it’s long). Sometimes the crash is actually in Windows (if it says user.exe or kernel.dll or something about insufficient GDI resources, it’s often a Windows problem) rather than in the application you were using.
Think the problem through logically. Use whatever you do know. For instance, if you can check email, but you can’t send email, the problem is probably in the outgoing mail settings of your email program. If you can send email, but you can’t get email, check your incoming mail settings and your password for the account (on some systems you can send email without a valid password, but you can’t receive it). If you just installed a new version of the drivers for your video card, and when you rebooted Windows you couldn’t get a display, it is unlikely that you have a hardware problem. Reboot using your emergency boot disk (you have a current one, right?), get into Windows in safe mode, and change the video driver back to something generic. Don’t go pulling the video card out of the computer or worry about replacing it or the monitor. (Yes, you laugh — but I heard a supposed support person tell someone to do that once.)
Be methodical. Do not change three things at once. Try one thing at a time. If the first doesn’t fix your problem, set it back the way it was and try the next thing. Hey, you documented what you changed, right, so it isn’t hard to put it back that way, is it?
If the problem is with one particular program, remove it. See if the computer behaves properly without it. Then restart the computer and install the latest version of that program. Keep everything else closed. Does it still crash?
There is a time to walk away and take a break. Totally away. Out of the building. Get food. Walk the dog. Play steal the flag with your kids. Just do something that is 100% unrelated to the problem you’re working on, because you can push so hard that you’ll get frustrated and burnt out and do something rash. Be good to yourself, clear your mind, and relax. The problem will still be there when you’re ready to go at it again, and you might well have come up with a fresh approach in the meantime.
Know when to get help. Everyone has to do that sometimes.
Think logically about who to call for help. If you can’t get your email on your new computer, it might seem reasonable to call up the computer company. But what sort of message did you get when you tried to get your email? Did you read that carefully? Did it indicate that the problem was with your user name or password? Then you should really be calling whoever provides your email, probably your internet service provider, because the computer company can’t help you fix that password. They can just tell you where to put the proper password and username in when you have them.