Booting from formerly raid 1 disk

A raid 1 array should still be functioning correctly if one of two drives went down. You will need to replace the defective drive at which point the raid controller will rebuild the array from the good drive, returning you to the same point you where at before the failure.

Or did you have a raid 0 array. In which case the failure of one drive will cause the loss of all data on the array.

IMHO
the only good backup is on an external drive in a box not plugged into anything

I have (had) a raid 1 array but the computer does not want to boot. It shows the critical condition message on a line starting with id #1. Do I have to assume that the #1 means the hard disk that is connected to the "sata_raid_1" connector or, as there apparently could be more than one, the #1 raid?

I have unplugged the #1 hard disk and now I get the message that I should insert bootable media. In other words the #2 hard disk is missing its boot record, correct? Then I have unplugged the wrong one?

I would try plugging that drive back in and unplugging the other, keeping them on their original ports

beyond that you will have to consult your raid controllers manual

Just did that and now I get a message that windows could not start because of bad or missing "hal.dll".

Can I install the "hal.dll" I have on another xp?

Thanks a lot.

give it a try as a temp solution to recover any data possible but it sound like the data got corrupted on both drives somehow, so I wouldn't consider it a long term solution

Thanks for responding to my questions. I still have one and hopefully the last.

Can I take one drive out and install it in a portable usb sata drive holder and read it? The raid is already not working and harm is already done, right?

entirely possible and may be your best route at this point