I used to use Adobe Digital Editions all the time for reading epubs from my library, but they have recently switch over and support kindle format so I generally use that.
You need to make sure that you have the latest version of Adobe Digital Editions installed on your Windows 10 computer. I think it's 4.5.126523 version but could be newer as I don't use it anymore since switching from my Nook over to my Kindle. You should be able to get the latest version from here if needed
http://www.adobe.com/solutions/ebook/digital-editions/download.html (be careful during the install and read each section carefully and avoid installing any bloatware during the install process it sometimes comes bundled with a Norton Product, simply uncheck it during the install).
Then you need to open Adobe Digital Editions and make sure your install shows that your Windows 10 machine is "Authorized". Check the help menu for both the version and authorization.
Then you need to check here
Control Panel\All Control Panel Items\Default Programs\Set Associations
"Associate a file type or protocol with a specific program"
Look for .acsm
Select it and if it is not showing Adobe Digital Editions as the "Current Default" you need to
Select it and click the "Change program" button top right and browse to your Adobe Digital Editions here
C:\Program Files (x86)\Adobe\Adobe Digital Editions 4.5\DigitalEditions.exe and select it.
Please let us know how things work out.