Dead iMac 2006 white intel

iMac was moved carefully from the desk to the floor when cleaning the desk. Once that was done I lift it back up and tried turning it on. I get nothing, no fans, no lights, no sound from hard drive - dead. I tried another Power cord, same thing. Replaced ram, pram reset etc, no difference. The only thing I hear if I put my ear against the back of the iMac is a clicking electrical noise that begins as soon as the power cord is plugged in. Is it the psu board that has died? Is it worth fixing? Any help is appriciated!

A clicking noise suggests to me that the hard drive has died. Since however you describe it as an "electrical" clicking noise, it could be the psu, or, the logic board .

Worth fixing? Only you can answer that really. Check out the costs of replacement parts such as the psu and the l/b, and if they're more than or close to the cost of a replacement iMac, consider a newer machine.

Go on vacation for a week, then try it when you get back.

This worked for me when my hard drive failed. All I heard was a clicking noise from the hard drive. I went on vacation, ordered a new SSD while on vacation, came home and turned on my iMac before I took it apart and it booted right up. Go figure. I replaced the hard drive with the SSD anyway and don't regret it a bit.

Adding a little to what zacster has said, pull the power cord plug from the wall while you're 'away'. Seriously, the advice is sound, there have been several instances of users disconnecting their computers completely from any power source/supply, leaving the computer alone for a day or three, and then rebooting it - successfully.

Why/how? Something to do with resetting of the psu, or something else 'inside'. In other words - a mystery.

If it doesn't work, you're back to having the iMac analyzed for faults, and repairing or replacing. Good luck.