What could cause a computer to boot from a secondary SATA drive instead of the primary?

I have an SSD with Windows 7 on it as a primary drive, and a secondary HDD with an old Windows XP install still on it. This system has been working fine for a few weeks, but suddenly the computer started booting up XP from the secondary drive.

The SSD doesn't seem to be broken, I could access all my files on it even when it was suddenly showing up as a secondary drive. When I unplug the HDD, the computer will boot from the SSD again, and when I plug it back in, it'll continue working fine for a few restarts, until it'll suddenly boot XP again.

Both drives are SATAS, and the SSD is plugged into port number 1. The only major thing I changed before the trouble started was turn off paging and indexing for the HDD.

What could be causing these problems?

ETA: After looking at the BIOS: At the times when it's booting wrong, the SSD doesn't appear in the list of drives at all, so it's not just a case of wrong boot order.

Cass

Posted 2011-09-08T20:08:53.623

Reputation: 201

3Do you see any issues with your system clock? It is possible the bios boot order could revert to a different order if the battery is dead. – MaQleod – 2011-09-08T20:13:14.677

Answers

Based on you saying that at times when it fails, the SSD does not appear in the boot order at all, I believe that your SSD either has a slow start time (see if your BIOS has option of adding a start delay of a few seconds).

That being said, the changes you made should not have affected anything and if you were not advised of setting a delay in any advice, and as it recently started, I believe that your SSD could be failing.

I would check to see if your manufacturer has either any updates available or a health test you can run against your device.

William Hilsum

Posted 2011-09-08T20:08:53.623

Reputation: 111 572

Agreed: The life-time of an SSD is much shorter than for an HDD and the failure rate is much higher. Buying an SSD is a calculated risk. If the SSD is still under warranty, try to get it replaced. – harrymc – 2011-09-13T06:48:18.127

It's like that you'll need to go into the BIOS (Esc, F1, F5, Del) while starting up and change the boot disk to the SSD rather than the HDD.

As for what caused it, not sure.

tombull89

Posted 2011-09-08T20:08:53.623

Reputation: 6 533

I've seen something like this on a microAtx system I have with a weak power supply. Sometimes there's not enough power right at boot to spin up the hard drive, and it will try to boot from the optical disk instead.

Joel Coehoorn

Posted 2011-09-08T20:08:53.623

Reputation: 26 787

My old power supply failed in that way - it would be OK with one hard drive plugged in, but with two it failed. – ChrisF – 2011-09-12T19:42:51.227

The jumper settings on the mainboard or the hard disks could also be causing this.

Sudipta Chatterjee

Posted 2011-09-08T20:08:53.623

Reputation: 308

Do motherboards still have jumpers? I haven't had to user jumpers , especially on a motherboard, for quite a while. Although if your motherboard has jumpers, it could affect which drive is being used for booting. – Kibbee – 2011-09-12T19:06:39.260

As far as I know, SATA drives do not need jumpers. – Cass – 2011-09-14T11:24:41.203