How do I remove a BeOS partition? Once I installed BeOS 5 PE onto its own drive, it completely disappeared from Windows and DOS. It just doesn't exists according to them. All my other drives and OS's exists to BeOS, but not vice versa. What can I do?
I just want to remove the partition so that I can then instal re-install BeOS onto a bigger drive. First, I want to get rid of the original install, though.

First off, Windows cannot read the BeOS file system. As far as I know, there is no way to access BeOS from Windows. BeOS, on the other hand, can read and "mount" many different file types, so Windows files can be accessed from BeOS.
What I've done is created a small windows partition named "Inter OS" for swapping files between the two OSes. That way, BeOS never has access to the main Windows drive. And with a small program available from BeBits called "wxmount," "Inter OS" is automatically mounted by BeOS on startup, so I never have to manually mount anything.
As far as deleting the BeOS partition, you don't really need to, unless you really want it on a bigger drive. In which case you need a partitioning tool, such as Ranish Partition Manager (Freeware). It installs within Windows and will let you create and delete partitions.