Power supply is to small for my COMPUTER 300 watt rated it is a AGI HP-3507f5w wanted to know if any 750 watt atx power supply will work?What makes you think it is too small?  Are you trying to upgrade something?

No, it is crucial that you buy a quality unit from a brand such as Corsair, Seasonic, XFX.etc.  You should expect to pay at least $1 for every 10w that the unit is rated for.  Also, consider how much you actually do need, why 750w?  That is a lot for most systems.One of my video cards says I need 300 watt power supply, after a COUPLE weeks would not boot up until I PULLED the card?What is the full spec of the system including the video card, 750w is LIKELY way more than you will need?Gigabyte mother dual core 1.8ghz 2x2gb ram ddr2 DVD burner 2 cooling fans hd 2600 pro 512m ddr2pci-e dual Dvi-I/tvo &  PCI card that RUNS 4 Bnc camerasThen 750w is way more than you will need, you would be wasting your money.  Does it not work in its current state?  It is possible that your current PSU is faulty, not that it's not powerful enough.

A decent 400w unit such as this would be more than sufficient: http://www.newegg.com/Product/Product.aspx?Item=N82E16817151076&cm_re=seasonic_oem-_-17-151-076-_-Product