The power supply has pretty bad reviews. Like I dont even think they are selling that model anymore and there is hardly any information on the web.
I would change the PSU to something like this http://www.amazon.co.uk/Corsair-CX750-Builder-Series-Bronze/dp/B008RJZR40
Remember you should never...
Yes, you should definitely change your PSU. Thats most likely why your PC is crashing. The PSU is not powerful enough. I would go for a 450w -600w power supply just for future purposes if you ever want to upgrade.
Never go for the minimum, though.