Yes, CSM is the option to enable booting to the older devices from pre-UEFI boot days. But, I'm thinking that the 1050 doesn't have a "dual mode" so to speak. I remember my EVGA GTX 970s had both Legacy and UEFI vBIOS from the factory, so you could either run CSM for legacy support(was running with X99 setup at the time)or disable CSM for full UEFI boot support. Just a look at folks on HP forums with similar system in that era are having the same issue. My guess is that the 1050, or possible the model the OP has, only supports UEFI boot and the system is hanging trying to properly boot. Had a look at HP download section for the model in question, the only BIOS update listing is from February 2012.