2004 Suburban Won't Start - Need ideas

I have a 2004 Suburban 2500. No problems with the vehicle until a couple of weeks ago it wouldn't start. I drove home from work, parked and turned the vehicle off. Got back in 30 minutes later, turned the key and nothing. Didn't turn over, no clicking, no sound at all. All the lights worked fine. Tried to start it over the course of 2 days and finally it started. Took it to the dealer and they said a cell was dead in the battery which they replaced. Two weeks later same thing happened. Tried it for a couple of days and one day it just starts up. This time I just kept turning the ignition key from off to start and on about the 20th attempt it started. Took it back to the dealer but they can't reproduce the problem so they say they have no idea what is wrong. Any ideas? It is completely unpredictable at this point.

check and make sure that there is not any corrosion on the battery cables at the battery, actually take them off and look at them.

almost sounds like a starter. Have someone check how much current your starter is drawing

I don't have passlock on mine, and don't know if you do...but here's a post from the Silverado Forum you might want to read.

http://www.automotiveforums.com/vbulletin/showthread.php?t=544603

Here's an idea for you from someone who has experienced it. I have a 2003 Sub. and it has had more than its fair share of electrical problems. One of them being that it will be running fine and then I will turn it off and next I know, it won't start. I actually just had it towed tonight for this problem and they supposedly "fixed" this 6 months ago. They told me then that it was wiring problem in the steering column and that they had to put in a new wire harness. Problem solved..........until now. Don't know if this helps.

I have a 2003 Suburban. Three times my suburban has failed to start. Engine light comes on, lose the clock, and when I turn the ignition only a clicking noise is made. When I remove the keys the odometer and speedometer needles rise. Twice boosting has started the vehicle, third time unsuccessful. Vehicle was towed to GM dealer and left over long weekend. I visited the vehicle to recover some items and found no power at all to open locks etc. Two days later the GM dealer started the vehicle without boosting and called to ask me what the problem was. Explained it to them as this was second visit to dealer. GM Technical is involved and cannot explain problem as it cannot be replicated by dealer. Again dealer says battery, alternator, cables etc is fine. GM is going to keep vehicle for rest of week to see if no start can be replicated. Does this sound like yours?