The safest and smartest way since you have a non-working system currently is to start fresh, format the drive and do the installer again, not choosing the SuperViaAta. Honestly, thats the route you should take. It will take longer, but your results will be untampered.

The alternate way, the removal is done from single user mode -s at darwin prompt
sudo bash
cd /System/Library/Extensions
kextload SuperViaAta.kext (To verify it's there, thats the name of it, etc)
rm -rf SuperViaAta.kext
reboot and -f -v the prompt the next time.

Good luck!

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System: M2N Plus SLI, Hazard 10.6.2
Video: NVIDIA GeForce 9600 (512MB- NVEnabler)
Processor: AMD Athlon Dual Core 6000+ ~3.2Ghz
Ram: 4GB (800mhz DDR2); Audio : Realtek (Voodoo HDA)
Disk 0 - 500 GB WDC (SATA; Snow 10.6.2- LegacySata)
Disk 4 - DVD-DL (Sata)
Network: Nforce 5 (RTL8169)