'.............but there is no reason to tolerate a program that freezes your computer regardless of file size...........
Your PC may freeze because you've hit an area of RAM at the high end which is faulty and you don't use it that often. Because your HD is caching, your PC has used up most of its resources and servicing interrupts gets more flaky. There are some issues for the OS, depending on which version and what you've got set in the disc/memory management options. If you've got a number of background tasks running without realising it - the CPU load just mounts up.
So, you import all your files, hard disc caching away like grass growing, then hit an edit function - I'd be surprised if the editor offered the chance of a clean exit BEFORE it tried to manipulate all that photo data in memory and cached on HD. So you can either wait a very long time, or Ctrl/Alt/Delete - and that can be quite unpredictable.
Try Collage on say a P90, without downsample before import, and you're most likely to crash and burn trying to escape from a seemingly frozen editing package! VOX