iTunes questions
 

I don't mind iTunes, it's relatively accessible to dummies and avoids most of the REALLY irritating features of WMP. But what is with the ticks next to the songs? Why is that whenever I accept the offer to download the latest version of iTunes a good percentage of my 1000+ songs lose their ticks?

Bear in mind her I have absolutely no idea why songs are ticked, I just know that if they aren't, the program goes to the next song that is ticked. Even this wouldn't be a problem if there were some sort of command to toggle or select all songs, but as far as I can tell the only way I can do it is to go through and select each unticked song individually. They're kidding, right?

And why is it that the dreaded exclamation mark appears seemingly at random? Sorry, can't find that song, just tell me again where the original is please? Leading to a massive search through my network to find which of the music files that a combination of PC's and Mac's find to hide songs contains the song I'm looking for.

As usual the absolute worst feature about Mac's, namely their help function, is of no use whatsoever. Any plain English suggestions would be welcomed.

The way to 'tick all' or 'untick all' on a PC is to click any tune then use the 'edit' menu to 'select all', then right click in the main window and from the little menu that appears, choose to tick or untick all the selected songs.
You can also use the Ctrl key and mouse to select individual groups of songs for ticking or unticking.

I don't know about on a Mac 'cos I don't use one, but I'm sure the Mac must have an equivalent way to perform these operations.