The XDA Developers site seems to be down at the moment, but you need to find a post there to the effect of "How to completely remove Voodoo lagfix".
Just keep checking the site and when it's back up, go to the Fascinate forum for Android Development and it should be on the first page.
Once you've removed Voodoo, then you can restore a stock kernel and ROM.
If you have Clockwork recovery installed, your best bet would be to download the Clockwork backup from this post, put it on your SD card and flash it with CW:
http://forum.androidcentral.com/fascinate-roms-hacks/38029-how-escape-force-close-loop-hell.html
That'll return you to a stock ROM with only SU and SuperUser.apk installed, rooted, but otherwise completely stock.
Not sure how you installed your kernel, but to restore the stock kernel, you'll have to use Odin and flash the stock kernel from this post:
http://forum.androidcentral.com/fascinate-roms-hacks/34819-how-go-back-stock.html
But, before you do ANYTHING, you need to disable/remove the Voodoo lagfix, otherwise you'll just make things far, far worse.
And just to say... this seems to be yet another example of why Voodoo should be avoided like the plague. Nothing but trouble.