Hello, Can someone please tell me if a GTX460 will run on my xps420 power spply as I am looking to upgrade
Will it run? The answer to your question is "maybe... and even if it does, not very well".
The best bet is to invest in a more powerful PSU, at least 500W. Make sure the unit is purchased from a reputable company with good Powersupplies: XFX, Corsair, OCZ, Antec, etc... Don't go with one of those no name companies.