I can't remember in the 2 1/2 years of using PixInsight on my same Windows 7 64 computer that PI locked up to where I would have to exit the program via the task manager.
True for me as well. I typically register from 100 to 200 subs from an 8300 based camera and it did not do anything like this until the most recent version. Sometimes it does clear after a wait but the last time (158 subs) it did not. In my case it is W 7 64, Haswell i7 with 16 gigs and the images were coming and going to a Sata 3 SSD with lots of room.
OTOH, it is my main machine so there are other things running in background. Of course, the machine has not changed and it still had most of the same other stuff running on it with the older PI versions that did not have the issue.