xmp boot

So today i was playing normally , my friend brought his hard drive so i can play games on his drive on my pc , everything was working fine , after that i unplugged the hard drive and play normally on my games , i opened pubg to play a game , after like 10 mins the games becomes extremely laggy ...

Hey guys I just recently bought new memory ddr4 16x2 3600 CL18 and it's not able to boot with XMP, it's locked into my old speed which was 2600, how can I go about fixing this? My rig: i7 7700k 1080 TI 16x2 DDR4 Z270X-Gaming 5 Im not very experienced with XMP not sure what it does all too...