I have a Compaq Presario Sr5710y. It has a 250 watt PSU. I upgraded my graphics card from on-board graphics, to an Evga 2GB gt 640 super-clocked. Now this new card I installed doesn't have a PSU spot on it, so it gets it's power from the graphics card slot. It's working great and I went ahead and purchased a 400 watt PSU. I'm not the most tech savvy, but I watched some how to videos and it seemed easy enough, so I went ahead and installed the new 400 watt PSU. It seemed to start up just fine. But I heard a noise inside the computer that sounded like one of the cords on the PSU got caught in the fan on either the graphics card or the PSU itself(if that's possible). That is when I started experiencing these lines going through the screen on my display. It only showed up on white screens. I wasn't sure what to do so I shut down and reinstalled the old PSU and also reinstalled my graphic card drivers. That fixed the problem. So now I'm thinking of taking my pc in and letting Best Buy install my new PSU, so that I don't have any complications. But they want like $50! Now my pc seems to be running just fine. It's not hot or anything, no crashes. Games work fine and look great. Is it safe to keep the 250 watt PSU? I just have the basic hardware, only thing I added was the new graphics card. Also, would it be safe to re-install the PSU myself, maybe just make sure I don't get any wires in the way of anything? I so don't wanna hand over fifty bucks to Best Buy on something I might not need, or something I could do myself. Thanks alot for any info you can give!!