[Q] Please help, htc logo after lockscreen topic

i bought yesterday and used htc one m7 from sprint, i wanna used with gsm, cause im from another country, so a installed a rom(viper one) and when it gets to the lockscreen it shows de htc logo and nothing more, and then a coule minutes later it reboots. ill ad a photo. at first i tought i got bootloop bt i can unlock the phone and it shows the htc logo like it was starting the phone,

also im s-on but i dont know if that says something.
heres the info from bootloader hope its helps.
***tempered***
***unlocked***
M7_WLS PVT SHIP S-ON RH
HBOOT-1.57.0000
OpenDSP-v32.120.274.0909
eMMC-boot 2048MB
Sep 24 2014, 16:58:42.0
:crying::crying::crying::crying::crying::crying:
PS: when i bouth it it did have system, they said, flash viperone and youll fine.