Hello, I'm fairly new to Linux.

Kde neon/kubuntu 17.04 doesn't seem to boot from live usb on my main system. It just gets stuck on black background, with blurred pixelated white text overlapping each other on it which is not readable.

I've tried adding nosplash parametre to kde neon boot menu entry with no effect on the result.

Ubuntu 16.04 and 17.10 boots up from live usb with no problems on the same system.

My system specs are:
Intel i5-4460
Nvidia gtx 970
Asrock b85m pro4

Help is appreciated.

Well, here's some things you could try.
A. Rewrite the image using UNetbootin
B. Turn of EFI or UEFI if it is on in the BIOS
C. Verify the image you downloaded.