Dataflows failing due to credentials.

This is more of a question than a request for assitance. 
Within the past month most of my Dataflows have been failing to Refresh. The error comes back as "The given credential contains a property with a null value."
There are two issues that happened at the same time.  One, my computer crashed and I had to get a new one. Two, our IT department "Reset the SQL Servers".  
I've figured out that can recreate these Dataflows, even though I reeeeallly don't want to recreate them all.
Do either of the issues above look like something that could cause this problem?