Frank, if you navigate to Applications/Utilities/Disk Utility you'll get to where you need to be to repair permissions. I don't really even know exactly what permissions are (some OS thing) but they can become damaged any number of ways, and need periodic fixing. If you neglect this for too long your computer can get very sketchy.
In the window you'll see all the hard drives connected to your computer. Find the one that has your system on it and click on it. You should then be able to click on the options to verify, and repair permissions. I just skip the verify and go straight to repair. The program will run and you may see many, many messages pop up as permission problems are detected and repaired. Eventually you'll get to see a message stating permissions repair is complete. You can quit the program. It's a good idea to repair permissions before and just after you install new software, especially OS upgrades, if had a power failure while the computer was running, or if it just starts acting like a PC!
There are other maintenance tasks which the OS will run automatically if you leave it on 24/7. Otherwise you should do them manually. In applications/utilities/terminal is where you go. You'll see what i'll call a command line. Type in the following:"sudo periodic daily" only don't include the quotes, and hit enter. The program will ask you for your password. Type that in, hit enter, and the program will run. It may take a minute. Once that's done you'll get the flashing cursor back. Repeat the process only this time type in: sudo periodic weekly. You won't need to re-enter your password. This one takes the longest and could be three or four or five minutes. As long as you hear your hard drive making thinking noises there's no reason for concern. Once that's finished repeat one final time, only substitute monthly for weekly. Upon completion you can quit the program. There's an inexpensive program call Macaroni which can do all this for you, but I just do it myself.
Apart from not letting your system drive (or any) get so full it can run itself, there really isn't much other housekeeping to do on a Mac, AFAIK.
Hope this all helps. I'm really curious to see if you're able to get your computer to see your monitor. My reasons for choosing the more expensive Eizo over the Apple or LaCie monitors were the ability to do a hardware calibration, and the five year warranty.