I have Win 10 running PicSender on 3 laptops now, but have not seen that issue. All three were updated from a previous Windows version (two from Win 7 and one from Win 8) that were running PicSender with no issues. I did not do a clean Win 10 install, which may account for your problem if you did.
You might also be able to roll your computer back to its previous Windows version. I know this is possible with a Win 10 update install, but not sure if with a clean install.
If Jeff's info does not help, please let us know, and I will do some more research on a possible fix.
Edit: With a quick internet search, it seems as if your problem is a common issue for some people when updating to Windows 10, with quite a few posting ways to install 3.5 framework.