My windows are starting to fog and lose the seal!
Of course Hacienda Builders is gone.
I am trying to find the window company that supplied the windows.
House was built in '05.

We can't possibly know. Sometimes the manufacturer is printed in white (barely visible) in a lower corner. If not, call 2 window contractors and ask them to give a quote, and while there they might be able to identify the brand.
I'm not sure about a 7 year guarantee, but there's hope.