RCW, Microsoft updates vary in size depending on what is involved, what you have installed on your PC and how much drive space you have free, it may take a while to update. My work laptop (3+yrs old) takes around an hour to update and reboot and we only pick the critical updates to install on these machines. Let it be and come back in 30 min or so to see.
I built my last Windows PC back in 2005 so it is VERY old and still runs Windows 10. I rarely use it so every time I power up it wants to do a Windows update and a Anti Virus definition update. If I know I'm gonna need it, I turn it on the night before and let it do its thing so when I'm ready to go, it is as well. The last time I watched it update back in July (needed it to run a Garmin update) It took almost 2.5hrs to update. A SSD will help as will more memory but you will need to jump through a few hoops to get that SSD to work and copy your data over. Do your homework and see if it will support the newer SSD's before you go buy one and attempt an upgrade
I do most of my personal computer stuff now on an iMac from 2013 that still gets all the iOS updates from Apple and still runs great. 7+yrs old and still supported by Apple. I have that one set to download and upgrade overnight so we are good to go during the day. I used to be anti Apple but the ease of use and supporting of the platform for family is a lot easier than Windows. My FIL was a habitual Yes clicker and would get infected multiple times a week. I loaded Ubuntu on his PC which cleared up the issue and when it was time to get a new machine, we got him the iMac. Email, Web Browsing, Favorites, all easily moved over and he loved it. Visits were no longer spent reimaging a PC but being able to visit. When he passed, the Mac came to our house.
The only negative I see on the Mac is that you can't throw in an additional hard drive or increase memory, at least not on the iMac. I also need an external USB DVD drive to load the tax software on. Yes I could download it off the web, but when my download speeds are less than 1Mb, the external drive makes more sense. On the plus side, it takes up less space, no noise, great screen and you can back up your iPhone to the Mac instead of the iCloud. The wife loves it because her favorites sync between her phone and tablet right to the Mac, same with her email.
There is a little learning curve to figure out where things are, but you can load Chrome and Gmail apps easily and be online quickly. If you are going to replace the PC, definitely give it a look.