How identical are those 100 computers? If they are reasonably close and especially if they are on a network this technique should work very well:
- Make a bootable Clonezilla CD or USB stick
- Install one system, do all updates and customizations
- Boot the clonezilla and run a save disk to a network or external drive
- Reboot without Clonezilla
- Boot each of the other systems with Clonezilla and do a restore disk
Oh, BTW, you would need to change the host name for each computer and might want to add/change the user for each but that is another story.
There are other possibilities such as setting up a PXE boot server, or using one machine to clone all the drives but the first is complex and the second is really about the same as the Cloezilla method.
Hope that is helpful.