I had this problem... but I fixed it in the most unusual way which you probably wouldn't want to do.
I broke my A600.
I didn't mean to! It now takes an hour (literally! I timed it) to boot up from cold - the CAPS lock light just stays on. Once it's up, it'll reboot happily, but it takes that long to come up the first time. However, for some bizarre reason it also boots up perfectly off its disk, which I'm sure it never used to do. I broke it by sticking 1MB SIMMS in the trapdoor slot in place of 256KB SIMMS - not sure why it damaged it but there we go.
What I used to have to do was make a bootdisk which ran HDToolbox, probed the bus (which told the HDD to spin up) and then rebooted, and it was fine from then on. For some reason, though, I always needed to probe the IDE bus before the disk would spin up.
Maybe that'll help you - who knows?
