Error 1327 Itunes folder

Basically it comes down to owning an external hard drive. It used to only let me open itunes when the hard drive was on because of the itunes folder being contained on the hard drive.

Anyway my brother was mucking about with my hard drive and now it's changed it's name (it moved from being known as G:/ to I:/ and cause of that iTunes won't open, let me uninstall or do anything with it)

Any help would be appreciated and I promise to just keep the iTunes folder on my pc.