He,

For example :i installed AppleACPIPlatform.kext in extension folder. After reboot it gives a kernel panic.
How can i uninstall this kext and replace the backed- up kext. And not have to reinstall the OSX.
I've read: after reboot press f8.
There are -v -s -x

or

boot with -s, then type
Code:

mount -uw /
rm -R /system/library/extensions/AppleACPIPlatform.kext

Can you pleace give some advice on this, thanks.