BootCamp partition shows in Disk Utility, but it's not bootable

I resized the disk using Bootcamp Assistant, put the Windows CD in the mac and rebooted, waiting for the installer to start. Surprisingly nothing happens. BootCamp partition doesn't show at startup and all I see is the gray screen. I booted under Mac OS and checked in Disk Utility if BootCamp partition was there - yes it was! It's also on my desktop. I tried restoring the drive to one partition, verified the disk and the permissions, tried with Windows XP and Windows 7 DVDs and it's all the same.. I've installed Windows on several macs and this is the first time something like this happens.