Replacing ido with iswitchb results in not being able to get to "/c/" in Emacs

[KARR, DAVID]

I was using the released version of Emacs in Cygwin 1.7.29, and I moved to the 
"test" version of "24.3.90.1" to test some fatal error problems.

I noticed that it complained that "iswitchb" is obsolete, so I switched to 
"ido", which is apparently recommended to replace it.

When I started using it, I immediately noticed a blocking problem with it.  I 
map "/cygdrive" to "/c" in /etc/fstab.  In Emacs, with ido, when I type "/c/", 
it gives me the following completion choices: "{etc/ | proc/ | cygdrive/}".  I 
don't know what I'm supposed to do now.  If I just continue typing the path I 
need, it replaces "/c/" with "/etc/", which isn't what I want.  It doesn't 
appear that I can get to "/c/" with ido.