I need some help with Excel VBA, currently I have the following line
of code:

PeakCPU = Application.VLookup(ServerName, Workbooks(Workbook).Sheets
("Server_Utilisation").Range("$C$25:$L$8100"), 7, False)

This looks for a string in an already open spreadsheet but I'm running
out of memory due to the number of spreadsheets I am working with.
What I want to do is amend this so it will look for the data in a
spreadsheet that is not open but stored on my C drive.

Please advise how I need to amend the formula, I believe this is
possible but can't find any examples.

Thanks.