If by "accelerator" you mean an overclocking tool, that is definitely your issue right there. You cannot, I repeat, cannot, overclock a video card without adequate knowledge of cooling. It's not something you should be tampering with if you're overclocking and it hasn't even occurred to you that your crashes may be related. What you need to do is disable overclocking and uninstall that tool before you fry your video card if it's not already too late. You may have managed to burn in defects in the gpu or ram which don't go away even after you bring the clocks back down.
With an ancient card like a Geforce 4 honestly I'm surprised it's still alive at all (I have a geforce 4 ti on its last limbs in a linux box but I've barely used it since I bought it many years ago), but it is not smart to take cards that old and overclock them. All processors, silicon chips in general, have a lifespan which is mostly indicated by heat exposure. Even at optimal temperatures you can't reasonably expect a chip to live more than 6-10 years, but overclocking them adds a lot of extra internal heat even when you're cooling it adequately, which drastically reduces lifespan. So you get a great video card and OC it with good cooling you can expect 2-4 years of life, and your card is already past that time so what you're doing is sort of abusing it on its way out.
Stop abusing that poor old dog and invest 50 whole bucks into a newer video card if you need a little more performance. If you get yourself a used GeForce 6 you'll easily triple its performance, and I bought one on ebay for $50 a little while ago. Just make sure you get AGP (or PCI if you have a PCI card, ew, which is *not* to be confused with PCI-express).