I have recently encountered something new. My DVD/CD-ROM has stopped working and now when I start the computer, the black screen gives me a message "Configuring MBA Press Control+Alt+B" then the screen changes to "Press N to book from Network." I'm not sure if all of these are connected, but they all started happening at once. The computer sees the DVD/CD-ROM drive, but says there no disc in it when I have one in there. It doesn't matter if it's a music CD, software CD or DVD - it doesn't run. I haven't changed anything on the computer or installed anything new, so I'm not sure why this is happening and, as I said, if these messages upon boot are related to this problem. Any assistance would be greatly appreciated. Thank you.

"Configuring MBA Press Control+Alt+B" then the screen changes to "Press N to book from Network." The network adapter on your computer is bootable - it's capable of starting up your computer on it's own - it has a read only chip on it with a program on (boot rom) that is called Master Boot Agent. You are seeing that, though you didn't see that before, probably because it is in the boot order in your bios Setup, and none of the things listed before it (above it) are presently bootable. The thing that usually kills an optical (CD or DVD) drive first is the sleeve bearings in it's motor wear and deteriorate to the point such that there is too much friction in them and the motor can no longer spin at even 1X speed (the original standard audio CD speed) or will not spin at all. In that case, your mboard bios and Windows cannot deal with that situation, and will "think" there is no CD in the drive when there is one in it. Is your computer a laptop, or a desktop or tower computer? A Vaio can be either, and I can't tell from the info in your post which you have. It's model number would be helpful too. You have not mentioned whether your hard drive is booting - going by your info so far it probably isn't.

My Sony Vaio is a desktop model - Model # PCV-RS312(UC). I know that the BIOS was set to use the DVD/CD ROM drive as boot, so I went in yesterday and changed that setting to my CD ROM drive (there are two drives on this computer - a DVD/CD ROM and a CD ROM). My CD ROM is working fine, so far. However, it didn't change the MBA and Network messages I get at the beginning of the boot process. The BIOS doesn't even have a setting for Boot from Network (I compared it to our other computer's BIOS - an emachine -, which DOES have a listing for Boot from Network). I'm not sure what you mean when you ask if the hard drive is booting. After the messages, the computer boots and runs just fine (although it takes quite some time for it to boot, much longer than our other computer). How can I find this out - will the computer boot up if it isn't booting from the hard drive? Is it booting from another source? How do I know this? And what can I do about it? Thank you for your help!

"...Sony Vaio is a desktop model - Model # PCV-RS312(UC)" I have no idea what the UC stands for. I'm assuming it's a US model. There are three US series of PCV-RS312 - one has no letters after PCV-RS312, the other two do. I'm assuming yours is one of the former. I looked at the User manual for your model - there is no detailed info in it about what you see in the bios Setup screens. If you still have the original Sony software insrtalltion on your hard drive, you probably have the same manual in your Programs listings somewhere. According to info about your model series on the web, your mboard probably has a built in Realtek RTL8139 networking chipset. The only time I have seen MBA related messages while booting a computer, it had a 3Com network card in a PCI slot. Do you have a network port on a card in a slot space? If you do, that card did not come with the computer originally, from the factory. If you have such a card and are not using it, removing it from the mboard will eliminate the MBA messages while booting. You don't need two networking adapters to connect two or more computers together on a local network (e.g. at your own location, where you can use any of them) if you are using a router. Some bioses have something in their boot order settings where you can specify a bootable network card in the boot order, some do not. However, that doesn't necessarily mean a bootable network card cannot be booted from if it isn't in the boot order list. If the network card has boot rom, it may attempt to boot first in any case. It could be the MBA related messages were being displayed before when your DVD drive was working properly, but because the DVD drive was working properly and was detected quickly, the messages were displayed so fast that you didn't notice them, or they were displayed behind a Sony logo screen and were therefore hidden. You don't have to respond to the messages if you don't want to - if you don't, and if no password has been set up for the MBA making it necessary to enter it in order to access the computer, the display of the messages just times out after x seconds and the computer continues to boot normally, according to the boot order settings. On the computer with the 3Com network card I encountered, the MBA had a password, which I didn't know because it was a discarded computer I had acquired. I had to remove the card in order to boot the computer normally. Some networks card have the boot rom in a socket - if you remove the boot rom chip it then isn't bootable - but that 3Com card has the chip the MBA is on soldered into the board. You may find that if you disconnect the data cable connection to the DVD drive, you will no longer notice the messages. If you try that, unplug the computer, or otherwise switch off the AC power to the case - you must do that whenever you connect or disconnect anything inside the computer case. You may need to change the jumper on the CDRom drive when you do that, if it is jumpered as slave and was on the same IDE data cable as the DVD drive, or if both optical drives were on the same data cable and were both jumpered cable select, you may need to plug in the end connector on the three connector data cable into the CDRom drive, if it is presently plugged into the middle one and is by itself on the data cable when the DVD drive is disconnected. "After the messages, the computer boots and runs just fine.." Okay then, if your computer is booting Windows fine, there's nothing wrong with your hard drive. "...will the computer boot up if it isn't booting from the hard drive?" The mboard itself will boot fully if anything in the boot order in the bios Setup is bootable - it boots using the first thing that is bootable it finds. However, some bioses will only try to boot from the first hard or optical drive listed if you have more than one - if it is not bootable the bios may not try to boot from the next drive(s) in a list. "....although it takes quite some time for it to boot, much longer than our other computer" Taking longer to boot can be caused by many different things, even for a computer with the same mboard, ram, and cpu. A defective optical drive can certainly slow down the initial part of the booting.

Tubesandwires - thank you for your help and the wonderful explanation. It all makes more sense to me now. I will have to check into replacing that DVD/CD ROM as I think that explain the whole thing. I will at least unplug it and see what that does. But at least now I know what is happening, thanks to your careful explanation. Thank you!