i just updated my mobo and it is asking me to activate windows again

If you only changed mobo its should be fine sometimes according to MS it can take a couple of days before you get activated but i never had that problem i switched mobo without an issue

easy way to sign in if its giving you trouble right click on Desktop choose personalize when you get to that screen it should say you have to validate your account click it and your at the account page click validate or login using ms ac

Try the troubleshoot link. It will ask you if you've made major hardware changes recently. When you reply in the affirmative it will usually go ahead and activate thereafter. No long waiting period required. Try it, please! If you hit a snag, or this doesn't make sense, here's a Activation Troubleshooter - Use in Windows 10 - Windows 10 Forums tutorial.
HTH,
--Ed--

Gabriel Aul, Vice President of Engineering for the Windows & Devices group at Microsoft, users who are facing this problem can simply contact support from within Windows 10 and they will activate your "New" Hardware lets hope its faster then with Windows 7

Hmm Reading different things from the MS official site
"If the hardware configuration of your Windows 10 device changes significantly (e.g. motherboard change) Windows may require re-activation on the device. This is the same experience as prior versions of Windows (e.g. Windows 7 and Windows 8.1). The free upgrade offer will not apply to activation of Windows 10 in such scenarios where hardware changes reset Activation."

I have switched all of my hardware except my Ram had no issues at all once i logged into my ms acc it activates without problems