Resolved Acer: can't boot from CD-ROM

Hi. While trying to run Windows Defender Offline I discovered that my Acer MC605 won't boot from a CD-ROM. Checked with 2 different bootable CD-ROMs - same problem. Went into the BIOS, and checked the CD&DVD drive is listed under peripherals on the generic screen. Went to the "Boot order" screen to ensure CD&DVD was the first option, followed by HDD - OK, save and exit.
Then I noticed something strange. In the "Boot order priority" dialog, each line (HDD, CD&DVD, External, etc.) can be fine-tuned by pressing Enter and choosing a device in that category (in theory: in practice, since I have only one device of each type, that's the one whose serial number shows). The line "HDD ", for example, offers the s/n of the hard disk. But the "CD&DVD" line doesn't open at all, just sits there and doesn't respond to Enter, or show any serial number.
So the optical drive works fine (read/write) once Windows is up and running, and is recognised by the BIOS, but isn't valid as a boot option. Grateful for any suggestions.

 

Hi G Watson, Sounds like you have SF trouble. It might pay to run SFC /Scannow to make sure all is well. I don't know about W8 so there might be a Repair program to run instead. Neil.

 

Hi Neil, Steve, and thanks for input.
Neil: do I assume "SF" = system files? There's no SFC for W8, but all diagnostic options W8 does have found no errors.
Steve: I tried the "FixIt" tool, which also found no errors.
In both cases, I suspect the problem is upstream from this stuff, because it seems to occur during boot and well before Windows kicks in: once W8 is running, the optical drive works fine.
I see on the Acer website there's an update to the BIOS, but that really scares me, and if I should screw something up while trying to update the BIOS, then I'm really stuck a long way up the creek, because I wouldn't even be able to use the magic "reset everything to factory defaults" CD-ROM I burned, as advised by Acer, as soon as I brought the machine home from the store.

 

Have you had any Updates installed which may have affected the OS?
Had any other Software added recently?
It seems odd that it works when Windows fully opens. Neil.

 

Only the regular Windows updates, and no new software.
As I said, I'm pretty sure this is a hardware or a BIOS problem, as the anomalies start there (drive recognised in system configuration but not in boot order of preference).
I don't find it so odd that everything works under Windows, but rather that it doesn't work under BIOS!

I've now done what I confess I should have thought of first: I've posted a question on the Acer support forum. (So used to quick, reliable help on WindowsBBS that I instinctively turned there first ...) I promise I'll pass on any help Acer provides, in case others are having similar problems and are following this thread.

 

Hi Geoffrey, Just thinking again after Posting last night. Has anything been altered/dis-abled in msconfig or Management>System? Regarding Startup.

Hope you get an answer from Acer Forum. Neil.

 

OK, resolved. It has nothing to do with the BIOS version. It is this new UEFI bios that Acer is installing on their machines. They have an enhanced BIOS feature through their default Windows 8 image. There is a boot option in BIOS called "Launch CSM" (Always|Never - never is the default). This apparently stands for Compatibility Support Module. I tried it once, but it appeared to be for booting via ethernet, so I discarded it as not being what I wanted. Acer support however told me to activate it and continue, and it would eventually boot from CD-ROM, which it did.
Only minor problem - you can't leave it set to Always so that the PC boots from the second option (HDD) when it finds no CD-ROM in the drive: you need to set it specifically to boot from disk, and then reboot and unset it again when you've finished doing whatever you needed the disk for.
Also, the first time I used it it still didn't recognise the CD_ROM drive (i.e., didn't list its s/n), which is another reason I had discarded that possibility. But after having used it once, I noticed that in future it does list the s/n of the optical drive, which it must have logged into the BIOS settings somehow.
Many thanks anyway for helpful suggestions.