Broken power button on HP pavilion desktop

I've had an HP Pavilion a1020n desktop for a couple years now, and the power button has always gotten stuck once in a while. When I pushed it today it got stuck almost sideways and nothing I tried would get it back in place. I finally had to remove the front cover of the modem, and saw that one of the plastic pieces that held it in place was broken. I tried pushing the actual black power button inside the computer and nothing. I followed most of the troubleshooting tips on the HP website (holding the button for 5 seconds, unplugging power cord, etc.) and didn't get any results. I actually called HP technical support only to find that they don't really offer technical support; they just tell you that you have the option of sending the computer in to be fixed but ofcourse you will be charged. If anyone has any ideas on how to resolve this I would be so grateful! I have no problem replacing parts or taking it to be fixed, but it would be great if there is a way to start it up in the meantime because I have the majority of my school work saved on there.