This is my 24″ iMac an hour after it died. Yes everyone, it just stopped working!
Not a sound. I went online, via laptop, to the MacHelp pages. Hmmm. The logic board perhaps? Power supply?  I unplugged all the wires. I waited. I pressed the start button many many times. I left the room to let it (and me) have some quiet time. Not A SOUND. No hum, nothing.
And this was all hours before I was leaving for a week.
Never fear: I DO have Time Machine (which has absolutely saved me several times…) and a complete backup i.e. that little flat black box sitting just underneath.

This is what I came back to today. Husband had taken the beloved iMac to the hospital. Yes indeed, first they will install a new power supply to get it going to then see just what the problem is. But we think it IS the logic board i.e. motherboard. The inner workings of the computer and not to be confused with the hard drive.
So this is what I’m using for now. Thank goodness for the laptop. But I’m still missing some critical Photoshop files and really, most of my iPhoto files. I don’t transfer them over here on a regular basis.
So then, the question becomes: do I pay for this repair or go all the way and get a new computer? My operating system is Snow Leopard (up from Leopard just three months ago). A new computer would have  Mountain Lion. Of course, there is the money issue. But then again, we have known I would have to go the “new” route for some time: my machine is just so slow these days and has been having problems on and off. On the other hand, I just do NOT have time right now to deal with any learning curve involved in Mountain Lion.
Computer stories anyone? You DO backup, right????
And yes, I will stick with my older iMac for a while; let’s hope I can make it last through the year!