I recently bought a Low Profile GeForce 9800gt 512MB GDDR3 and I realized that in order to use it, I need a much better power supply. The one that I have in there is a 250watt and the video card requires at LEAST 400watts. Normaly this wouldn't be a problem, but my computer is a Low Profile (slim). It's a DELL Inspiron 531s. Now I can't find a power supply to fit in there. I've looked everywhere. So my only hope now is to change my entire computer case from a low profile to regular. I've already verified that my motherboard would fit in another case because it's a micro ATX. I'm just wondering if this sort of thing has been done before and if there is something that I'm not thinking about that could stop me from pulling this off? Also if there are any guides to doing this sort of thing a link would be MUCH MUCH appreciated. Thank you.

Here are my computers specs pulled from the dell website

Processors
Intel® CoreTM 2 Duo Processor E6420 (1.86GHz, 4MB L2 cache, 1066MHz FSB)
Intel® CoreTM 2 Duo Processor E6320 (1.86GHz, 4MB L2 cache, 1066MHz FSB)
Intel® CoreTM 2 Duo Processor 4400 (2.0GHz, 2MB L2 cache, 800MHz FSB)
Intel® CoreTM 2 Duo Processor 4300 (1.80GHz, 2MB L2 cache, 800MHz FSB)
Intel® Pentium® dual-core processor E2160 (1.80GHz, 1MB L2 Cache, 800MHz FSB)
Intel® Pentium® dual-core processor E2140 (1.60GHz, 1MB L2 Cache, 800MHz FSB)
Intel Celeron Processor 420 (1.60GHz, 512 L2 Cache, 800MHz FSB)
Intel® G33 Express Chipset

Operating Systems
Genuine Windows® XP Professional
Genuine Windows® XP Home Edition
Windows Vista® capable

For more details on Dell systems that run Windows Vista, see www.dell.com/vista.

Memory
DDR23 is a memory architecture that enables systems to improve performance and reduce power consumption. The amount of RAM you have determines how many programs can be executed at one time and how much DATA can be readily available to a program. It also determines how quickly your applications perform and how many applications you can easily toggle between at one time. Simply put, the more RAM you have, the more programs you can run smoothly and simultaneously.

Up to 4GB4 Dual-Channel DDR2 SDRAM (533MHz)



Hard Drives
The Inspiron 531s supports up to two hard drives, each with up to 500GB space - a potential CAPACITY of 1TB5 . And with Dell DataSafeTM and RAID 0 options, you can configure your storage to meet your needs, whether it's for storing large quantities of files, backing up system information and files, or improving performance with data striping.
Up to 1TB5 Multiple Serial ATA Hard Drives with both hard drives utilized.
Up to 500GB with Dell DataSafe, exclusively offered by Dell - a safe and simple way to help protect your memories from damage due to accidents, system crashes and other disasters.
Up to 500GB Single Serial ATA Hard Drive



Optical Drives
Multiple DVDRW 6, Combo, DVD-ROM configurations available
3.5" Floppy Drive and 13-in-1 Media Reader Available

Graphics


256MB ATI Radeon X1300 Pro
128MB ATI Radeon X1300
Intel® Graphics Media Accelerator X3000 (Intel® GMA X3000)

Sound
Integrated 7.1 Channel Audio

Ports, Slots, Chassis
Externally Accessible
Video: 1 DVI, VGA and 1 S-Video (with add-in PCI-Express video card)
USB: 6 Ports (2 Front, 4 Back) + 2 internal
Audio: Six back-panel connectors for line-in, line-out, microphone, rear surround, side surround, two front-panel connectors for headphones/microphone, integrated 7.1 channel sound
Network: Integrated 10/100 network interface


Expansion Slots
PCI: 2 Slots
PCIe x1: 1 Slot
PCIe x16 (Graphics): 1 Slots


Chassis
250 Watt DC Power Supply Backup battery: 3-V CR2032 lithium coin cell


3.5" Bays: 3 bays (two internal, one external)
5.25" Bays: 1 bays
Memory DIMM slots: 4 available



Dimensions & Weight
H: 14.2 inches (36.2 cm)
W: 3.9 inches (10.0 cm)
D: 17.1 inches (43.5 cm)
Regulatory and Environmental Compliance
Regulatory Model: DCSLF
Product Safety, EMC and Environmental Datasheets
Dell Regulatory Compliance Home Page
You want a mini ATX PSU...