Like I said, those who updated from a pre-existing installation of windows wont have a single issue.
The Skylake processors came out after windows 10, Most Skylake users will put windows 10 on their system as as they cannot upgrade them from their old Operating system because OEM software assigns itself to the hardware, new hardware=new OS. So why would they fork out money for win 7/8 then to upgrade to win10, when buying straight into win10 is cheaper and more time effective.
Sure retrospect it wouldve worked better, install win 7/8, install sims (and with it securom) upgrade to 10 and the whole problem would be solved. But thats not what is going to happen, and anyone upgrading their hardware in the future will have the same problem, as windows 10 becomes the standard for Factory builds aswell. Just hoping EA sees some sense in doing the work now while the numbers are few to prevent more issues in the future as more people upgrade their PC's.
Sims 4 does work though (at least the 48hr trial) which is a plus, maybe they can put its DRM onto Sims 3.
EDIT: Ok I stand corrected, I set up a dual boot to my old Windows 8.1 drive (OEM so thought this wouldnt work but it did) and ran the game, had the same problem. At this point I shift my focus from Win10 to Skylake.
So I went and checked my BIOS version and there was an update, nothing specific to this issue but I figured Id try it.
This did resolve the issue and I have been able to load into Sims3 fully patched (without EP's Ill try them later) where I couldnt before. So where Gigabyte specifically identified their update fixed this issue Asus did not.
For Asus users you need to go to http://support.asus.com/download/options.aspx?SLanguage=en and put the model of motherboard ie Maximus VIII ranger, select the OS and then expand BIOS. Mine for the above mention board were at 0401 an update to 0801 is there, download it and save it to a USB drive. You then reboot, go into BIOS and use the EZ updater to update the BIOS using the file you just downloaded to USB. When it starts WAIT, do not do anything until you boot into Windows, it may look like your PC is done but it switches off and on a few times when its done it booted up to windows for me (had to restart and re-apply certain BIOS settings).
Gigabyte have a similar update available http://www.gigabyte.com/support-downloads/download-center.aspx and choose your motherboard etc like the above example. I dont know how their BIOS update works but Im sure theres instruction on their site.