I did a win 8.1 Pro 64 bit upgrade over the top of Win 7 home 64 bit and the only thing I had to reinstall was Softube Slate and UAD 2 and WOW No More Crashes!   UAD still has the same issues but I worked hours on end for a week now with no problems . I'm really glad I did it and Windows 8 wasn't hard to get used to. So for $199.00 at Newegg I scored a 23" Touchscreen and that's running in tandem with my 46" screen , the touch screen makes a cool control surface.  Un till now win 7 with X3 was crashing at least 3 or 4 times a day .

Great news, now this is what a lot of people do not do...
Run Windows update several times.
Defrag
Now it is stable go and have a look at your Event Viewer for any possible issues under the bonnet (Check "Administrative Events").
Backup everything to an external hard drive (using Acronis True Image or something, BTW is now being sold at a discount, 40% off ends today!).

Yup - a nice full system image would be a great idea.
 
Bob Bone
 

It's possible you may have had some hosed Win7 system files or something and moving to 8.1 got you back to a clean system. Either way, though, I agree 8.1 is pretty solid.

I did backup my projects before I upgraded just to be safe

Yup but the point is you should get a backup now, a clone of your hard drive, to an external hard drive, in case something goes wrong in the future.
Anyway glad this is working for you.... well done..

At this moment, with a stable and solid system, should something happen to interfere with that, you would potentially need to install everything all over again, would would be a giant pain in the rear.
 
The suggestion from folks here is that to insulate yourself from having to do all of that, TAKE A FULL SYSTEM IMAGE BACKUP OF YOUR ENTIRE DRIVE (caps are for clarity only and have no intent to convey anger or any other anything).  If something goes South, you could simply restore your entire system to this exact state, from the system image backup, with everything working properly.
 
Many folks in the forum have expressed great sorrow at various times, from finding out the hard way that backing up the whole hard drive would have been a good idea.
 
So, that's all - folks just suggesting you avoid future pain and sorrow by taking a full image backup.
 
Bob Bone
 

From a full system backup perspective, under Win7 you actually had the option, but in 8 and 8.1 it has been buried.  I did find an option that's free to create full system backups called RecImg Manager, which you can find here: http://recimg.com.  I don't have much experience with this except that it created a full image of my office desktop (SSD -> mechanical drive) running Win 8.1 in about 20 minutes.  I've also got data backups running separately to that.  RecImg offers both full OS+Apps or OS+Apps+Data.  I opt for the data separate.
 
As with everything, a backup is only as good as the restore it's able to do, so whatever you use, make sure you verify that it actually is running when you think it is and that the restore is functional.
 
Hope this helps someone.

bobgassert
I did a win 8.1 Pro 64 bit upgrade over the top of Win 7 home 64 bit and the only thing I had to reinstall was Softube Slate and UAD 2 and WOW No More Crashes!

This is great to hear.  A fresh install requires a serious amount of time for a DAW!
 
Did you go directly to 8.1, or to 8 first?  Any other preparations?  In other threads, Noel B recommended CCleaner to clean the registry before an in-place OS upgrade.

Better still reformat the partition then install win 8 from scratch. That requires backing up your partition and having your data on another partition,