Locate the part on the window that needs replacing. Inspect it to see what the problem is and if the entire part needs replacing or just a portion of it.
Identify the type and model of window you have. If the window slides up and down, it is double-hung and if it moves side to side, it is a slider. Windows that crank out are casement windows and windows that crank up are awning windows.
Find the Andersen parts catalog on the Andersen website and locate the parts for your particular window. Find your window type, scroll down and look for the part which needs replacing. Once found, write the number down on a piece of paper.
Call Anderson after finding the part or go to any online retailer that sells Andersen window parts to order the necessary piece.
Remove the old part and install it by following the manufacturer's instructions included with the part.