My husband has a Compaq Presario SR5413WM : Additional Specifications Processor Type: Athlon 64 Hard Drive Size: 250 GB System RAM: 2048 MB Operating System: Microsoft Windows Vista Home Premium Processor Type: AMD Athlon LE-1640 / 2.7 GHz Cache Memory Type: L2 cache Installed Size: 512 KB RAM Installed Size: 2 GB / 4 GB (max) Technology: DDR2 SDRAM Storage Hard Drive: 1 x 250 GB - standard - Serial ATA-300 - 7200 rpm Operating System / Software OS Provided: Microsoft Windows Vista Home Premium Software: HP Photosmart Essential, Adobe Reader 8.0, Microsoft Works 9.0, Norton Internet Security 2008 (60 days subscription) Graphics Controller Type: Integrated Graphics Processor / Vendor: NVIDIA GeForce 6150 SE TurboCache supporting 128MB Optical Storage Type: DVD±RW (±R DL) / DVD-RAM - Serial ATA Read Speed: 40x (CD) / 16x (DVD) Write Speed: 40x (CD) / 16x (DVD±R) / 8x (DVD±R DL) Expansion / Connectivity Expansion Bays Total (Free): 2 ( 1 ) x front accessible - 5.25" x 1/2H ¦ 1 ( 1 ) x front accessible - 3.5" x 1/3H ¦ 2 ( 1 ) x internal - 3.5" x 1/3H Expansion Slots Total (Free): 2 ( 0 ) x memory - DIMM 240-pin ¦ 1 ( 0 ) x processor ¦ 2 ( 1 ) x PCI ¦ 1 ( 1 ) x PCI Express x16 ¦ 1 ( 1 ) x PCI Express x1 Networking I would like to upgrade the psu but cannot find any information on how to go about doing this. Also I am wondering what the most watts this model can handle. Also if possible without changing the psu, would this model be able to handle a pci e video card requiring 300w to 450w psu? One more thing, if changing the psu out is required, would there be a need to alter the pins on the motherboard? Any help would be greatly appreciated. Thank you.