Most people don't multiboot with windows. With linux many want to try several flavours of the OS, and upgrade to a new kernel or whatbnot just because it's free.They happily venture into partitioning and installing boot loaders, then blame it on linux when it doesn't automagically support and guess their intented setup. See I can rant too ;-)

If your Kanotix BH4 root filesystem hasn't been touched there's no reason it wouldn't boot anymore. If you need help, post your menu.lst and the output of 'fdisk -l'. Please identify every partition in that list.