First, I have to say this is terrible performance.

If you can't open for instance your task manager anymore, that's a Windows problem, not a Bitcoin Core problem. I would have hit the reset button much faster than that, but that's probably why I don't use Windows.

My advice would be to start over, but not before upgrading your hardware. To compare performance: on my old Linux laptop with slow CPU but 16 GB RAM and Bitcoin Core's chainstate directory on SSD (with the blocks directory on HDD), I can sync the full blockchain from scratch in just over 24 hours. If you insist on running Bitcoin Core, and if your computer can handle it, I suggest to add at least 8 GB of RAM, and a solid state drive. With your current hardware you're probably better off running a less demanding wallet (such as Electrum).