I would like to know how hard it would be to replace the power supply in my computer.Ihave a Xps 420 with a 375w psu and would like to upgrade to the 425w psu.I can order one from dell for 72.00 plus tax and shipping.I would like to run the Ati 4850 graphics card instead of the ati 3650 256mb that I have now.Do you think the 375w psu will handel the card safely?I have a Q6600 2.4 and 4g of 800 mhz ram and 750g hd.thanks for any help!!