My pc is screwed

fdisk won't pickup a partition and I want to wipe everything but I can't as fdisk shows a logical partition in the extended partition but when I choose to delete the logical partition it says none exist, yet I can see it when I choose to view the partition table. It is just over a GB in size....no idea what it is. It maybe the linux swap but that should be non-dos so basically something is buggered..

Does anyone know of a way to totally wipe everything?

Will writing zeros to the drive do it?

Currently the drives are all messed up too. My C drive is showing as A: so who knows where the floppy went :)

Bear in mind this has to be done from linux or dos....I don't have an Windows installed.

Thanks.