Installer partitioner won't allow selection

[Marie Dow <mariedow@earthlink.net>]

Greetings:

The Sarge installer's partitioner won't allow me to select partition 
settings, either "Use as:" or "Bootable flag:." Spacebar should toggle 
through the selections, right? The current setting on the partition that 
I need to use are "Use as: Do not use" (should be /) and "Bootable flag: 
on," which is correct.

Here's my situation. Installed on the hard drive is WinXp and Knoppix. 
I'd installed Sarge also last week, but decided to reinstall (stupid). I 
used Knoppix to delete all files in the Sarge partition. The previous 
Sarge install had put the bootloader on the MBR. (GRUB gives me an error 
15 now if I try to boot from the hard drive.) I booted with a Knoppix CD 
to double check that the former Sarge partition was empty and it was.

I keep thinking that this must be something simple, but I can't think of 
anything else to try.

I'm a rather green Linux user who is supposed to do a presentation on 
Thursday using this computer. Help! I'm using my wife's Linux box and 
e-mail to make this contact.

Elmer E. Dow