yes, that is most likely your power supply, what model you currently have? The BP550 should be fine, though I always recommend OCZ for gaming setups.
EDIT: this can also happen if your circuit isnt able to supply enough power to the power supply, so when it goes to charge the capacitors, the momentary dip will cause a system crash. Do you have any large appliances on the same circuit? I doubt this is the issue, but its worth checking.
OCZ SXS600w: http://www.zipzoomfly.com/jsp/Produc...odlist=froogle