My LG G2 stuck at boot logo

Hi there,
I acquired a LG G2 smartphone the other day and went straight to try rooting the phone, I really enjoy tweaking my phones to suit some tastes the Stock Rom doesn't have, I did a NAND backup, rooted the phone and went ahead to install CynogenMod, the device stuck on the boot logo, I tried running the NAND backup, which is also stuck on the boot logo, what causes such problem? how can I solve this since I have already voided my warranty?
