Hello, this is my first post on this board. I have a TI 84 +, not the Silver model or C/CE or whatever. I upgraded to the newest firmware. It gives a bunch of functions that are PrettyPrinted, like ∫_0^π f(x) dx . What I want to discuss, though, is Σ_{n=1}^N f_n . This worked for a little while, I could get it to do sums. I don't know what I did to it but it fails to work, now. It gives me:

Err: Archived
1. Quit
2. Goto

My first guess was to just go and re-install the firmware. That did not solve the problem. I have no other ideas, does anyone else have any? This is the only function that gives me a problem in this way.

One of your variables must have been archived. Verify that by:
[2nd][Mem][Mem Mgmt][Real]
Scroll down and anything with an "*" (asterisk) before it, is in Archive. [Enter] to toggle.

Hmm! It seems I had Archived everything E ... Q. I've UnArchived them now and my summer works again.