Excel issues Help?

Google is your friend.
Do a Google search for "microsoft office add-in sgin in has stopped working"

Some hints:
Unintall the existting Miscrosoft Live Add-In Sign In on your computer, then install the updated version 1.5....that's exactly the cure for your problem.

http://www.microsoft.com/downloads/en/details.aspx?FamilyID=cc4beea9-b678-4fd3-b66c-ce7f953b0085
------------------------------------------------------------
Rename the main file:

C:\Program Files\Microsoft\Office Live\OLConnector.dll

to

C:\Program Files\Microsoft\Office Live\OLConnector.dll.old
--------------------------------------------------------------


By the way, this is not an operating system question.

Electro
April 2011