[CentOS] isolinux on a pendrive from disk 1

Thu Jun 5 18:56:55 UTC 2008
Jerry Geis <geisj at pagestation.com>

Hi

I just grabbed an 8gig thumb drive, took disk 1 centos 4 i386,
copied the isolinux directory files to my thumbdrive, then ran syslinux 
-sf /dev/sdc1
on the device plugged it into my laptop  and it does not boot.

Is there a step(s) I am missing to get a bootable thumbdrive with centos?

Thanks,

Jerry