OrionSkybourne1 Thanks for the dxdiag. Please clear as much space as you can on your C drive, which is almost completely full and could be the direct or (more likely) indirect reason you're unable to play. I realize it's not easy with such a small drive, but you can offload some data to your external drive.
If you want to install games on the external, you may need to either erase it and format it as NTFS, or partition it and format the new partition as NTFS. You can do either one by clicking Windows key-X and selecting Disk Utility.
Once you've cleared at least another 15 GB or so on C, try again to play. If you still can't, please look for new errors in the Reliability Monitor. Hit Windows key-R and enter "perfmon /rel" without quotes, and you'll see a chart of errors and updates with a column for each day. Today is on the right.
Look for an error that happened at exactly the time of your most recent attempt to open Sims 4. If you find one, double-click it to see more details, then copy that info and paste it into a reply here. If you don't see a new error, check back in an hour or so—the Reliability Monitor doesn't always update right away.