how change root partition?

[windos_no_thanks]

I am also trying to use reiserfs for / and when I try booting without an initrd the kernel won't do it? Does it not recognise reiser without a module?

A kernel configured the same way as the default knoppix kernel has the reiserfs support as a module (because that way you can get rid of it if you don't use reiserfs) If you recompile the kernel and specify that you want the reiserfs code directly in the kernel you will be able to boot without an initrd.