Startup issues/partitions 10.5.8

Hello
My employer set up my work Mac Powerbook (2.66Ghz Intel Core 2 Duo, 4 Gb RAM, OSX 10.5.8) with two partitions: MACINTOSH HD and STORAGE. Despite this naming, ALL files -- software and data -- were put in MACINTOSH HD.

My notebook worked terribly; there was little room in the partition and everything was slow. I tried to get my IT Dept to remove the other partition, but they wouldn't. Finally, a friendly tech moved all my data to STORAGE; he also moved all the Desktop settings &c. The computer still didn't run as well as it should, but it ran better. When I turned on the computer, it opened in the STORAGE partition.

Recently, after a startup, the computer reverted to opening in the MACINTOSH HD partition. While I can get to my data, I cannot access my Address Book files and the like. I cannot get the notebook to recognise the other partition at startup.

How can i get the computer to open in the other partition?

To clarify: the operating system and other software is running from MACINTOSH HD. The Desktop, Library folders &c, are on STORAGE. STORAGE does NOT as an option if I startup the notebook with the Option key held down.

Best

You can't start up from the storage partition if it has no OS on it. What you will need to do to access the storage is copy it onto an external drive, or install an OS onto the storage partition with what you want on it.
Personally, I would just create a new user account with what you want on it, name it storage, and then remove the storage partition.