One of our company's IBM NetVista computers had a faulty CD-ROM drive. I replaced it with a new DVD-ROM drive and the start-up BIOS sequence started being very slow, up to 3-4 minutes, before booting from disk. Even then, after it starts booting Windows XP, in the middle of XP boot there's a delay of a couple of minutes during which there's nothing but a blank screen.
Once Windows XP starts up, everything is normal.
The user found this unacceptable, so we installed the old CD-ROM back (restoring previous configuration), but the problem is still there.
We even tried disconnecting the CD-ROM and the disks, and the BIOS boot sequence was still slow.
What do you think could be causing this?