Excell links changing directory names

[Mashed]

brief description of the recent problem I had when copying & linking my spreadsheets

I copied from Explorer the prvious months files into a new folder(G drive) ie say Sept files to October files-spread sheets should link aotomatically

When I openend the new file the path name had changed from G:\XXXXXX\xxxxxx\xxxx to W:\XXXXXX\xxxxx\xxxx.
I saved all new files but did not reboot my computer and it still showed the drive as 'W'
I switched my machine off before I went home and the problem had corrected itself when I started the machine the next day.

We run on Domains here and all have access to the G Drive which has a shared directory in it.

Any answers as to why the G: is changing to W:?????

Thanks in advance