The hardware came with preinstalled Windows which is OEM. Normally change in hardware cause trouble. Try read this:

support.microsoft.com/en-us/help/20530/windows-10-reactivating-after-hardware-change?ranMID=24542&ranEAID=kXQk6*ivFEQ&ranSiteID=kXQk6.ivFEQ-Y9NmwSFR5XtIO6YEoQ5bTA&epi=kXQk6.ivFEQ-Y9NmwSFR5XtIO6YEoQ5bTA&irgwc=1&OCID=AID681541_aff_7593_1243925&tduid=(ir__w1x3whcobskfrkvrxmdf30kppu2xhimvjwtjbfgx00)(7593)(1243925)(kXQk6.ivFEQ-Y9NmwSFR5XtIO6YEoQ5bTA)()&irclickid=_w1x3whcobskfrkvrxmdf30kppu2xhimvjwtjbfgx00

Nowadays, you cannot just install your licensed Window to any computer. Microsoft ties hardware and software in database, unlike last time. If you need to transfer to another hardware (I presumed including change the CPU, not just mobo), need to de-register from old pc and then activate again to newly installed pc. Last time I heard only can transfer up to 3 times only..... unless you install in illegal method