what are specs of the PC?
have you changed the location or size of the page file?
when you load the games, can you look on task manager/Performance/Memory tab and see how much free you have
Windows shouldn't just crash if you use half your ram, it should be able to run easy in the difference, although pc might be a little slower.
Closer you get to no ram, more PC has to use page file and even if you have an NVME it will still be slower than ram.
Still shouldn't crash as you should have Virtual memory left to use.