The spin up/spin down issues you are experiencing suggest a flaky DC board; check the CubeOwner forums for more information on this. While you're at it, check the PRAM battery and replace this too if it reads a marginal voltage - crazy things can happen if not.
A 3.5" SATA drive doesn't fit once you've added the necessary adapter, so you need to do some significant modification for this. A 2.5" SATA drive on the other hand might be the go with the required adapter - it should fit OK.
JB
A 3.5" SATA drive doesn't fit once you've added the necessary adapter, so you need to do some significant modification for this. A 2.5" SATA drive on the other hand might be the go with the required adapter - it should fit OK.
JB