I have the same problem here. My first problem was "About This Mac" crashes, so I employed the solution pointed here
http://osx86.wikidot.com/known-issues#toc6 using the AppleSMBIOS.kext found at netkas. After the reboot, 'About This Mac' works, but now all my USB devices aren't working except for the USB mouse [the keyboard is a PS/2 attached to a USB adapter].

Looked at System.kext [same as kernel 9.2.0] in System Profiler and it says all Dependencies are satisfied.

Any help regarding this issue is greatly appreciated.

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Mac OS X Leopard 10.6.2
Intel Core i5 650 3.20 GHz (Threads: 4 Cache: 4MB Socket 1156)
ASUS P7P55D-LE
Seagate 80 GB SATA 7200rpm HDD (OS Drive)
Seagate 320 GB SATA 7200rpm HDD (Data Drive)
Built-in Via VT1828S HD Audio 8 channel
Built-in Ethernet
Palit Nvidia GeForce GT 240 512MB 128bit HDMI PCIE
2GB Kingston DDR3 RAM 1333
Monitor: Viewsonic VG1930wm 19" Widescreen
Lite-On DVD-R/RW IDE Drive