Weird "Disk Boot failure" message

When I start Windows Vista, if I don't have the install disk in the DVD-drive it won't boot, giving me the error message "Disk Boot Failure". As long as the DVD is in the drive, it proceeds to the screen "hit any key to boot from disk" (which I don't need) and then boots up normally. This began when I installed Vista a few months back. Any ideas on what is going on?

 

Check your BOOT Sequence in your BIOS.....

 

right idea

 

It should be HD, HD, CD-Rom correct?

 

Most of the time is Disquette 3 1/2 then HD-00 or HD-01 then CD-Rom.

 

Ok, thanks. I'll check when I boot up in the morning, but I'm fairly certain I've got it set up that way already, so if there are any other possibilities please post. I'll try a few different combinations tomorrow morning and see if that solves the problem. Thanks for the help thus far, and let me know if there are any other common fixes.

Sam