I'd look at newegg.com and geeks.com for -> Socket 775 <- motherboards. My bet is that's what you are seeking.
HOWEVER be aware the OS will not survive the move. As this is well discussed I'll stop here.
Long story short; Old GFX card dies, I buy a new one only to find it doesn't fit my BTX board/case. Got my hands on an ATX case now I just need to find a very specific board that will work with the new GFX card and all my other outdated hardware.
Microsoft Windows 7 Home Premium 32-bit SP1
Intel Core 2 Duo E6400 @ 2.13GHz 37 °C
Conroe 65nm Technology
3.00 GB DDR2
Dell Inc. 0WG864 (Microprocessor)
128MB GeForce 7300 LE (Dell) 59 °C
149GB Seagate ST3160812AS (RAID) 33 °C
HL-DT-ST DVD-ROM GDRH10N
TSSTcorp DVD+-RW TS-H553A
Creative X-Fi Audio Processor (WDM)
New GFX: GTX 650 Ti
Also, if there is another componnent or two that would be cheap and easy to replace (I'm looking at you, RAM) that would make it easier to make a board fit, I'd appreciate the suggestions.