It probably installed new drivers that don't work with your sound device, it did that to me all the time.
What kind of sound card do you have or are you using onboard sound?
You can go into Device Manager, Sound Video and Game Controllers, Properties, and try rolling back the drivers.
If it doesn't show that option you can try and reinstall the drivers from the media that came with the computer, if you have it.
Or you can go into Device Manager and uninstall your sound device.
Tell it to uninstall the drivers for it as well, when asked.
Reboot your computer and see if when it reinstalls your card the sound starts working.
I had a lot of problems with my Sound Blaster card in Windows 10, so much so that I switched the speaker cables to the inputs on my motherboard and use the onboard sound instead.
There are a whole lot of things that can fix this problem, but it's customary to answer a few basic questions for us. What is the Make/Model of your computer? Is it a desktop PC or a laptop? Did this computer come with W10 pre-loaded on it from the factory? Or is a self-built rig or custom-rig? If it's a self-built or custom rig, we need Make/Model of your Motherboard, CPU, GPU card, and PSU Make/Model and Wattage. You can download the free SPECCY diagnostic from piriform.com to give you all the specs you need except the PSU (Power Supply) which you will have to open your computer case to get to it's label. Then post the results output text file back here to this thread where we can look analyze it.
While you are looking to gather this information for us, there are a couple of easy things to try. However, before doing any kinds of Windows repairs on your own, we strongly suggest that you FIRST BACKUP ALL OF YOUR PERSONAL DATA TO EXTERNAL MEDIA! THIS WOULD INCLUDE YOUR LIBRARY FOLDERS FOR DOCUMENTS, PHOTOS, MUSIC, VIDEOS, AND ANY SAVED E-MAILS OR ATTACHMENTS.
First thing I would try is to run a Windows System Restore and "rollback" your computer to a time before yesterday's update, such as 2 days ago. This will often undo damage to windows from an update that installed a badly behaving component such as a driver or such. This procedure has very good results and will fix the problem in many cases. However, occasionally it can cause catastrophic windows crash, and your computer may no longer boot! This is why I have the big red warning about backing your stuff up before trying this. If this doesn't solve your problem, you may need to run one of the following: 1.) W10 in-place upgrade 2.) W10 reset from factory recovery software on your hard drive (Recovery Partition) 3.) W10 reinstallation from legit factory recovery media (Disc or USB stick)
If that fails, you may need to do hardware testing on your computer's components in order to resolve the problem. Since we don't know if you got to W10 by purchasing a new W10 computer or if you upgraded your older computer from an earlier version of windows or not, we're guessing on what you ran into. We can tell you that it's much more common for an upgraded W10 computer to fail from a weekly or monthly Microsoft update than a W10 computer that came pre-loaded with W10 already on it.
Mike's software the EaseUS TODO software is good. We have tested this on XP-W10. You might also take a look at MACRIUM REFLECT, another free backup image software. I personally have done more testing with this program, and have been installing it on every customer computer that comes into my shop. If fact I had a good customer who runs his business on W10 using QuickBooks Pro 2016 call me Friday to tell me his computer lost access to his QuickBooks and his business was down as he could no longer take credit card orders nor E-mail invoices to customers requesting payment. I picked his laptop up Friday night and ran diagnostics on it. It turned out to be a failed external usb hard drive causing his problem. I booted up the Macrium rescue disc and found his backup image file from Dec. 2015 when I sold him the laptop, restored the backup image to his hard drive in under 1 hr. and had him backup and going Monday morning--today! We only lost 1 week of data out of the last 5 years in doing so and he's back up and running in only 3 days!