brand new Asus N750JK doesn't boot anymore

Hello there!

I just bought an Asus N750JK ( IntelCore i7-4710HQ(2.5GHz 6M), 8GB DDR3, SSD 24GB + 1TB, NVIDIA GeForce GTX850M). It came with no operating system.

I wanted to install W8.1 from an USB drive, so I went into Bios, changed the boot order, saved the configuration and rebooted. The screen went black and stayed black since. No logo, no nothing. I tried everything to revive it, but nothing worked. So I called the shop for a return and now the fun begins: they claim I opened the back cover and tampered with it, which voids my warranty. At the moment, the laptop is in their custody, to be sent to Asus for an expertise. If they find no evidence of tampering I will get another one (or money back).

My question is: are they allowed to do that? Where can I read the warranty rules involving tampering with back-cover screws?

Thank you.

 

http://www.asus.com/support/images/pdf/e8549_nb-warranty-card_148x105mm_final_0827.pdf

They have the burden of proof, though. If they and/or Asus are unable to produce evidence that you tampered with it, then it's difficult for them to make that claim and you can fight for your warranty. Nearly all OEMs do not warrant a product once you have tampered with it on some level, though.