iMac won't sleep; Trackpad and Keyboard eat batteries

I love my iMac (specs at bottom) but this one had a problem sleeping once I got and connected the Magic Trackpad and Keyboard via Bluetooth.

Also, the batteries do no seem to last long. A few weeks? I had rechargeables and alkaline, but changed the trackpad batteries just last week and now it says 8%.

I set un-checked the Bluetooth Preference so the Trackpad and Keyboard could not wake the iMac. That, oddly, seemed to let the computer sleep properly
--> Huh?!?!?!?

Then, I now have to wake the iMac by the power button, and manually press the buttons on the Trackpad and Keyboard to get them paired.

I saw some threads about updating their software, but don't see how to do that from within the Preferences pane. Or is that old advice, now handled by Software Update?

I'm just puzzled by this stuff...



20-inch Late 2006
Processor 2.16 GHz Intel Core 2 Duo
Memory 3 GB 667 MHz DDR2 SDRAM
Software Mac OS X Lion 10.7.5 (11G63)

For what it is worth over years experimenting find the best batteries for keyboards, trackpads and mice are Energizer Ultimate Lithium. Currently experiencing six months on the keyboard and three to four months on trackpad/mouse. Worse results come from re-hargeables, but have just purchased Sanyo Eneloop 2500 mAh batteries which I believe are used by Apple.

Don't need no stinking wireless stuff, I love wires! Old dinosaurs love lots of wires hanging off their Mac. Never have trouble with batteries that way.