Licenses with a mobo change?

you'll be fine with the cakewalk stuff..

other  makers use different settings / setup and perhaps check for modifications (propellerhead stuff does) 


since it's a different cpu, I'd do a fresh install and perhaps specific CPU drivers are loaded as part of windows

OEM windows is as complete as any other, assuming it's not been altered by a PC manufacturer (e.g. it's a Microsoft Windows OEM disk, not a manufacturer's recovery/install disk which may have non-standard stuff in it).

However, the OEM license allows installation on only one PC. One way MS checks this is by tying the activation to the original cpu/motherboard, so installing a different motherboard may cause activation issues.

If that happens it's worth trying to activate Windows by telephone, explaining that you needed to replace the motherboard, but other than that the PC is the same one. I can't promise success, but it seem to have worked for at least some people.

If in doubt, try asking MS support for their view before changing anything.

I realise that you aren't using an OEM version but FWIW........

I upgraded my complete system including the mobo about this time last year. I'd heard all sorts of horror stories about how hard it was going to be activating Windows 7 on a new build as it had already been used on an old one.

The only things that stayed from that build were one hard drive and the power supply, the rest was junked. Windows 7 installed and activated with no problems at all. That was an OEM x64 version and I am UK based which may make a difference as I understand the hoops that Microsoft think you should have to jump through to be called a "system builder" are pretty much defunct over here in the EU where you just need to er.... build a system.

I once had to replace a defective motherboard in my DAW, and as a consequence had to re-authorize several plugins. 

This kind of took me by surprise, because I'd been upgrading systems for many years by replacing individual components - including motherboards - and never had any need to re-install or re-authorize any of my other software. It was only music-related software that gave me trouble. 
 
One vendor (Kjaerhus) was no longer in business, so I had no choice but to stop using that plugin. Another plugin (Amplitube) refused to re-authorize and kept complaining that it wasn't "installed properly", so I stopped using that one, too. But those were the only two that couldn't be brought back to life. SONAR and its bundled plugins were not a problem, and fortunately none of my most-used 3rd-party VSTs (e.g. Kontakt, Melodyne, Ozone, SampleTank) gave me any trouble.

There is no easy way to determine which of your plugins' licenses are tied to the motherboard short of contacting each of them and asking. But as long as all of your third-party vendors are still in business, you should be OK. Even those that limit the number of re-authorizations will help you out if you email them (not so sure about Waves, though).

Several Plugs could really killl your soul at this day...IK multimedia f.a.
But by all issues...
...if you change your motherboard...be sure it´s a much better idea to set the system also completely new up...
...a clean win 7 64bit is like "da Vincis" Mona Lisa...towards an "old Polaroid"...