Possible reasons for question mark folder?

I would personally insert "Run Apple Hardware Test" in between your 2 and 3; it'll tell you if there's anything wrong with the hardware in the system itself before you start swapping drives, which depending on the computer could save you a fair amount of time if it's an obvious logic board issue.

If we're talking general-purpose pro troubleshooting here, I'd also insert the step of hooking the old internal up to a USB interface and seeing if it's visible from another computer, which again can save you fiddling with things that don't actually turn out to be the problem, and if nothing else can help you allay any fears of the person whose computer you're fixing, since of course they never back anything up.

It is also, I suppose, at least theoretically possible for non-hardware firmware problems to cause a drive to fail to show, but that's pretty rare and probably not worth treating any differently from other hardware issues.

 

Can be a hard drive cable too, then look at connector on logic board.

Have seen systems where someone moved a critical system file, and that caused ?.

Also see directory damage cause this.

most of the time in my experience it's a bad drive though.

 

How would I do this?

 

Exactly like I said--you buy a SATA-USB converter (or PATA-USB, depending on the age of the computer), take the drive out of the computer, hook it up to the converter, plug it into another computer, and see if it mounts.

Multi-funciton converters that will handle both SATA and PATA drives and look pretty much like a little block on the end of a USB cable (plus a power supply brick) can be had for under $30, and tend to work well enough. If you do this a lot you can also get a toaster-style dock for bare drives (also cheap), or if rarely you could get a USB-SATA case, and just take out whatever drive you usually use with it to test another.

 

If you have another mac nearby, try kicking off the machine in Target Disk Mode (probably wont work) or simply boot off the OSX disks and check to see if the HDD is available in Disk Util..

Good Luck!

 

Keeping this simple, the question mark means that the Startup Disc can't be found. Have you tried starting your Mac while holding down the Option key? That should allow you to choose the Startup disc.

 

I don't have a question mark, my mac acts weirdly on startup, but doesn't boot, and the option key does nothing, and it ejects disks if I put them in. The problem was caused by a failed linux install, or a partition problem. I think that if I connect my HDD to another computer, I could fix the problem.