Hi,
Your machine is designed to run Windows 8 & 8.1:
http://h10025.www1.hp.com/ewfrf/wc/softwareCategory?cc=us&lc=en&product=6555968
Windows 8.1 is much, much, much better than Windows 7 and Windows 8. But if you wish to run Windows 7 you can install it and use Windows 7 updates to install drivers. You may ending up missing 2 or 3 drivers, please post back and people on this forum (specially Paul_Tikkanen) will help you.
Regards.