Umm, Novuake, almost all HP machines either come with a 300 watt or 350 watt PSU, in which both cases won't have enough wattage or amperage to handle a 460.
In fact, Walker's computer does only have a 300 watt psu. Source:
http://g1w0134.austin.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c01501563&lang=en&cc=us&contentType=SupportFAQ&prodSeriesId=3733093&prodTypeId=12454
He's going to need a better power supply. Minimum recommendation should be a quality 450 watt PSU or greater. PSU's are fairly cheap, and they're one of the best things you can spend money on for a quality part. It'll ensure stable performance and in some cases can reduce your power bill in the long run.