Just so you know your windows XP link is for Vista with Windows 7 upgrade (i would encourage you to go this route anyway though ).
I am assuming you don't want to loose your DVD drive as well you know as it probably isn't SATA. So that is going to be +$30.
So total you are looking at ~$400 for a pretty low end system (the processor is over 3 years old already, and the video card is pretty week as well) So really you are just saving your Power supply, case, & ram.
Some comparison shopping gives me these:
HP Pavilion Elite e9200z - $550 with (SVMY478761 coupon code)
* Genuine Windows 7 Home Premium 64-bit
* AMD Athlon(TM) X4 620 quad-core processor [2.6GHz, 2MB L2, up to 4000MT/s bus]
* 6GB (free upgrade from 4GB) DDR3-1066MHz SDRAM [2 DIMMs] -
* 640GB (Free upgrade from 500GB) 7200 rpm SATA 3Gb/s hard drive
* 512MB NVIDIA GeForce G210 [DVI, HDMI, VGA]
* DVD Burner
* 12-in one media reader
* etc. .
http://www.shopping.hp.com/webapp/s...p/psg/desktops/High_performance/e9200z_series
This is a much stronger PC that will last you a lot longer. You probably can salvage your Power supply and put it in here as well. Trying to save $100 bucks here is just being foolish in my opinion.
Still though i think this is short changing yourself at this price range as i can configure on cyberpowerpc's site:
Holiday Special III - $556.00 (No OS) or $640 with your OS deal above.
* Case Apevia X-Cruiser 2 Mid-Tower Case w/ Side-Panel Window & MultiMeter Display
* CPU: (Sckt775)Intel® Core™ 2 Duo E7500 CPU @ 2.93GHz 1066FSB 3MB L2 Cache 64-bit [-60]
* HDD: Single Hard Drive (1TB (1TBx1) SATA-II 3.0Gb/s 16MB Cache 7200RPM HDD [+26])
* MOTHERBOARD: MSI G31M3-L Intel G31 Chipset LGA775 FSB1333 DDR2 Mainboard
* MEMORY: 2GB (1GBx2) PC6400 DDR2/800 Dual Channel Memory [-44] (Corsair or Major Brand)
* SOUND: HIGH DEFINITION ON-BOARD 7.1 AUDIO
* VIDEO: NVIDIA GeForce GTS 250 512MB 16X PCI Express [-11] (Major Brand Powered by NVIDIA)
You could use your extra 2 GB of RAM here to bring it up to 4GB and this gives you a much faster processor and video card.
So i see your choices as :
-Spend $70 and get the PCI HDMI card to use in your existing system (probably won't satisfy you and you will get the itch to upgrade again very soon).
-Spend $400 to upgrade your current pc to a current low end entry system (may satisfy you for a year, but you will likely get the itch to upgrade at that point & spend another $300-400).
-Spend $550 to get a mid end system with decent video card (will last you at least 3 years).
-Spend $640 to get a mid-high end gaming system with good video card (will last you probably at least 4 years)