So to clarify more, it would void the warranty to the extent you damaged the PC doing the upgrade, or the user upgrade damaged the PC (for example if you Y split 4 fans and burned out header; or if your new fans were improperly wired to the board). Otherwise your warranty should be fine, but you'd likely need to put the PC back to OEM configuration before getting any warranty service on the PC (as troubleshooting is performed in OEM stock configuration). 
Does replacing case fans void the warranty? I would like to put quieter ones in but do not want to risk loosing the warranty.
Does replacing case fans void the warranty?