As someone that ran into this issue when I was on Win 7 also.  I wonder if there should be a sticky of some kind related to things to be aware of when trying to install Plat.  
 
While I did update to Win 10 on most of my computers, not everyone can or will.
 
As for the figure that three times as many Win 7 computers exist vs Win 10, I bet a large part of that is related to Business computers, not consumer ones.  

The commonly reported problem seem when Windows is not updated is in the knowledge base http://www.cakewalk.com/Support/Knowledge-Base/2016000033/Unable-to-register-the-DLL-OCX-RegSvr32-failed-with-exit-code-0x3
 
Some think there are too many sticky threads already. The knowledge base is an often overlooked resource.

scook
The commonly reported problem seem when Windows is not updated is in the knowledge base http://www.cakewalk.com/Support/Knowledge-Base/2016000033/Unable-to-register-the-DLL-OCX-RegSvr32-failed-with-exit-code-0x3
 
Some think there are too many sticky threads already. The knowledge base is an often overlooked resource.

Good call.  I'm thinking the only way one would find that is if they used the error code in the search there.  
 
I know when I had the install issue, I copied it and searched for it which lead me to a thread here on the forum.  

Noel Borthwick [Cakewalk]
I just responded to your support request:
 
From your report and screenshots you definitely have a problem on your Win7 system with the microsoft VS2015 redistributable installation. If that isn't installed properly SONAR will not launch. While we still support Win7 it is now a very old OS and is not being very actively supported by Microsoft, making it increasingly hard for us to support. 
 
If you want to continue to use Win 7 it is mandatory to keep the OS completely up to date with the latest Microsoft updates. Current versions of SONAR require the latest Microsoft SDKs. While SONAR definitely works on a fully updated Win 7 (we still test with it and there are still a few users who use Win7) we cannot replicate all permutations of older Win7 installs or assist effectively with system problems like this.
 
You could also try logging a support ticket with Microsoft about this if you cannot get it installed on Win7 since they might be better equipped to support it. I highly recommend that you move away from Win7 to Windows 10 as soon as possible to avoid headaches like this going forward.
 
Try looking at this MS Connect thread since there are some resolutions there: 
https://connect.microsoft...edback/Details/1574311

That's interesting Noel.
 
I'm [successfully] running Platinum on a Win 7 system which has never been updated since I took ownership of the machine in February 2012.

I am waiting for the reply from CW support since June !

I sent support an email almost a month ago and have received no help. I upgraded from X3 Prod to SPLAT and it crashes everytime I launch.

I upgraded for some projects I am working on and thus far...useless.

jppineau
Moreover, I have to deal with Firewire connections... and Win 10 has made a mess on my Offline Video Editing setup (on another machine, you guess) because of the IEEE 1394 thing
 
As for going to Win 10... It is a plunge in the unknown, but the reports we have about IEEE-1394 are scarrying me. I do not want to end with a DM-4800 as a paperweight...

Twice you mention an issue with W10 and Firewire - can you be more specific please (just curious as i've not experienced this this on my rig Focusrite LS 56 with F/W and W10)

Cheers,
Jerry

many users are receiving tech support for there issues as soon as same day.
that's already been reported.
however, ive also seen some users ignored by support asking invalid questions.
for example: wanting support for products that cakewalk no longer has support for, feature requests, asking how features work, the list goes on.
if your not getting a reply from cakewalk "there's a good chance" you might fall in to this category.