Excel workbook suddenly causing Excel to freeze up

See if the "Calculating" is showing in the Status bar at the bottom of the Excel window. Wait for calculations to complete.
Open Task Manager and check performance values for Memory usage.
For 32-bit Excel your more constrained. In 64-bit its about total memory. Once you start hitting memory limits things get bad slow and can lead to a crash.

SpillerBD said:

See if the "Calculating" is showing in the Status bar at the bottom of the Excel window. Wait for calculations to complete.
Open Task Manager and check performance values for Memory usage.
For 32-bit Excel your more constrained. In 64-bit its about total memory. Once you start hitting memory limits things get bad slow and can lead to a crash.

Click to expand...

I opened the task manager and under the "processes" tab EXCEL.EXE *32 says 1,298,548K under the Memory (Private Working Set).

I realize this is a lot. How can I reduce this? OR what do you recommend?

Best solution for me is switching to 64-bit and increasing your hardware's RAM. (At work I'm stuck at 32-bit and certain projects compel to use to my personal machine that is 16GB Ram and I7.)
Otherwise you need to make sure you are not duplicating data unnecessarily. That often means thinking of your tables with a Data Base mindset.
There are tools that can help utilize separate workbooks as one. I'm thinking PowerBI in the Excel Desktop, but you may not have access to any PowerBI tools depending on your Excel version. (see https://powerpivotpro.com/2015/10/what-versions-of-office-2016-contain-power-pivot/?nabm=0 also see https://powerbi.microsoft.com/en-us/)
The other option, which with 50 sheets suggest you have grown to , would be converting to an Access Data base. (ugg the switch if you're not already familiar with Access.)

If your route compels new computer, I would suggest this HP at the Microsoft Store. That would be top end, well rounded for any purpose. More business could trade Video card for Ram and downgrade from I7 to I5.

This computer is 16GB ram, Intel Core i7 processor. It's one of the best computers in the building. They special ordered it for me because I have so many big spreadsheets. But this particular sheet is giving me problems that I've never had before.

You're right. Access is the way to go. However, I have to print each tab off every month. Each assembly line uses the sheet to count their inventory on, and then I key their data back into the tab. There is a summary tab that has all of the info pulled to it. On the summary tab, it adds the price....blah blah blah You get what I'm saying.

You did indicate your using 32-bit Excel?

If it is memory, review https://support.microsoft.com/en-us/help/3160741/large-address-aware-capability-change-for-excel
I know a lot of companies still haven't switched to a full 64-bit environment, and the standard install is 32-bit.

Yes, sorry. I am 32 bit. I clicked on that link, but it doesn't tell me HOW to switch over to that.

At 32-Bit Excel you should max at accessible RAM at 4GB ,with the appropriate version and build updates. (Our IT got a computer for a user in my building like your's, but proceeded to Install 32 Windows on it. ) Without those updates, one only as 1.5GB max to work with.
To switch to the 64-bit Excel, Office must be Reinstalled using the 64-version. If using the download method, one has to look for the advanced download options.
What I have been assuming is that you are running out of memory and that overflow is going into the page file. Even to a SSD, that flip-flopping of data slows you down bad. So a 5400rpm drive can feel like molasses.
Just how big is the file according to Windows?

That makes perfect sense. I may talk to my IT and see if I can uninstall and reinstall with 64.

The file is 11,188 KB.