Changed drive letter...oops

Removed the "C"? what do you mean by that? All you had to
do was make the new hard drive the primary master by
switching the jumpers on the drive itself and it will
automatically map itself as C. Then set the jumpers on
the old one to make it a primary or secondary slave and
it will map as "D".

I added a second hard drive last night and transfered
all
my files from my old hd to my new on. Everything went
very smothly, i switched the hardrive so the new one
would be the primary and the old on the slave. I was
planning on reformating the old one and use it as
storage
but i could not do that until i changed the drive
letter.
I removed the C: from my old hd and said i had to
restart, i tried to add the C: to the new hd but it
would
not let me. Now right after the xp laod page my system
just sits idle with the win xp blue screen befor it
brings up my accounts. I am stumped, any help?
.