How to allocate a 2nd hard drive?

I agree - there is more information needed. However, let me take an educated guess. Normally, the phrase unallocated can mean that that portion of the drive you are referring to has not been formatted. Go control panel, Administrative Tools, Computer Managememt, Storage, Disk Management Local, and check the graphic display and it will tell you the status of the portion of the hard drive you are looking at. If it says unallocated, go to tools (I think) and perform a format. This is what I do all the time when using XP Hope this helps.  more

You might need to format it first, If on windows, go to my computer, find the drive and RIGHT click, select format.  more