Resetting factory settings - Toshiba L300

Hi

Can anyone help?

I am trying to speed up a friends Toshiba satellite pro L300. I was hoping to restore to factory settings as there is nothing on there that needs to be kept (easy to do on my own laptop via hitting F8 when turning on) but, having tried the hitting F8 method and also holding down 0 at start up, I have now been advised that, in all probability, the hidden partition for factory settings restore is no longer available (this being due to the laptop being originally installed with Windows Vista and at some point having been upgraded to Windows 7 - not sure who done this, the laptop came to my friend second hand)

My friend does not have any disks for the computer (as I said, she acquired it second hand). I have a a windows 7 disk (from my own lap top) but am not sure if this is any help as it is registered to my lap top (and I'm not even sure if the OS disk would help anyway! :-/)

Any idea what I can do? A very layman's explanation would be most appreciated, My technical knowledge only goes as far as running the anti virus scan and such. I am in way over my head here!!

Thanks in advance