Optiplex 755 dt crashes during boot with refurbished gpu installed

So I installed this gpu I bought off Newegg, but when I power the computer on, the fans spin for a second or two, then it makes a clicking sound and all the internal lights turn off and it restarts all over again. It's basically crashing within seconds of turning it on. The card I have is a low profile gt 740 from zotac it's 128 bit and 2gb of ddr3. I believe it's max power consumption is 64 watts which is probably the problem. I think I would need a more powerful power supply? Or is it that the motherboard isn't capable of giving the appropriate power to the card? The card is definitely seated properly.