Question mark on start-up

the ? means it cant find a boot volume. remove the external drive and try again. Make sure the boot drive is configure properly, and is working.

The old drives in Macs tend to suffer from "sticktion" where the platter brake sticks when it spins down at a power off and doesn't let go when powered back up. This was very typical of the older 40 and 80MB Quantum drives, and it did happen to other brands as well. The common solutions for them si to find a way to break them loose. Usually you'd try to tap the drive in the direction of rotation of the platters. So, you'd remove the HDD and tap it on the edge with the handle of a screwdriver or something. If you are comfortable with having open electronics, you can power up the system with the hdd attached and tap just after you power up. That way you'll have the drive motor trying to spin up the drive to help as you work it.

First things first, though. Be sure the cables are still connected right and all that.

Are all the SCSI ID's set correctly? The harddrive is usually 0 if it hasn't been changed. The Zip is 5 or 6, and the CD drive is most often 3. As long as the CD drive is not 5 or 6 and the harddrive hasn't been changed, then the ID's probably won't conflict unless the CD is on 0.

And also, the end of the line device should be terminated, and no other.

I suspect you know all this already. Just thought I'd throw it in anyway.

Can you hear the harddrive spinning up at all?

What is your level of expertise? Have you gone into this computer before? Getting to the harddrives in compact Macs can be a little tricky, and involves some amount of danger, although I don't remember exactly the case with the Color Classic.

Here's how to open the case:
http://lowendmac.com/compact/ccfaq.shtml#12

I found a Color Classic once on the side of the road a few years ago which had bad video, and it was during a strange time when I had decided to force myself to stop collecting old Macs, so since the video was bad, I put it back out on the street. What a silly time that was. Wish I had kept it. Actually, when I try to remember, I think it may have had Japanese markings on it, so it may have even been a Color Classic II. Egads. That's a little painful to remember now.

Anyway, that was my one and only experience with a Color Classic, so hopefully someone with experience here will give you advice. If you do need to get into the case you'll need a Torx screwdriver, about which there was a recent thread here:
http://www.applefritter.com/node/20660

If the HDD spins audibly or palpably, but there is no chk-chk-chk-chrrk of reading at about the time that raster appears on the CRT, the HDD may be feeling poorly, as you have surmised. A Disk Utility with more grunt than Apple's (Silverlining, FWB's ToolKit, Intech's HD SpeedTools, or Mt Everything might mount the drive and allow you to reinstall a driver at least, or reformat and repartition at most. Then again, rigor mortis may have set in, as Jon suggests. NDD and DiskWarrior are rather file utilities (directory rescue) than disk utilities (format, partition, install driver).

*Switch the CC off with the mains switch. If your wall socket is switchable and grounded, switch off but leave the mains cable connected so as to ground the internal chassis and the charge on the CRT. The charge should be bled off after switchoff, but if you are diffident about that, leave the CC overnight to ensure that charge has dissipated. If you believe not only in belt-and-braces but also a drawing pin into the belly-button, crank the brightness up to full while the CC is on, and simply remove the AC plug without using the rear switch. Pffftt! The charge is gone. Go back to * above. Unplug peripherals. Remove the LB in/out door (there may be two screws retaining it) at the lower rear of the case bucket by pulling the tabs down and out. Ground yourself and your clothing on any exposed metal of the chassis by touching it with one hand at a time. Withdraw the slide-out logic board and place it on an antistatic mat or (more likely) a piece of bubble-wrap that you have grounded first. Don't lose the four metal grounding loops on the underside of the board.

Lay the CC on its screen on a folded blanket or other soft but level surface. Use a Torx-15 driver with a long shaft to remove the four bright-metal screws that hold the bucket onto the front bezel. Unplug the mains cable, remove the bucket and replace the mains-cable plug. Marvel at the dust bunnies. If you clean out the dust bunnies with air, use canned air, and not a vacuum cleaner set to blow (and spray static charge everywhere). The HDD is shoe-horned in deeply above the LB space on the right (seen from the rear). You will need a pair of long-nosed pliers, or pickled-onion fingers, to remove it. However, first you have to unplug its data and power cables, which have restraining notches in the plastic housing. It's a pain, but thousands have done it. Now you must use the pliers to grasp the tab at the rear of the HDD's mounting sled, raise it just enough for its pawl to clear the notch in the case plastic, and haul it (courage! mon brave) upwards and out. Take the drive off its sled, grounding yourself frequently while you are handling it, and put it beside the LB with its mounting screws. Reassembly will follow the cliché about reversing disassembly order.

What happens now depends on several things. You can use up to 2TB from System 7.5.2 and upwards in your new(er) HDD. I use Quantum 1.2GB in CCs with 7.5 and 7.5.5, and a Seagate 2.1GB under 7.6.1. You may need to enable termination power (TP) on the drive, to enable termination on it (TE), and to make sure that its SCSI ID=0. How you use jumpers to do the first two depends on the make of drive, but having no jumper in any SCSI ID position will give ID=0 for all drives. Some older Quantum drives don't offer any means to select SCSI ID other than built-in 0.

While you have the LB out it is a good time to augment RAM (12MB total physical, but only 10MB 'seen') and VRAM, add a 10Base-T NIC in the LC PDS slot, and perhaps a 68882 FPU in the empty socket (unless there is one on the NIC, as sometimes happens), and certainly to replace the 3.6-V half-AA lithium PRAM battery. If your version of the LB has a CUDA switch (back left corner), press it for a couple of seconds after inserting a new battery into its cage.

de