#N/A Appearing evey once in a while

[Harold]

Hello Friends,

I have a file that is highly formulated. It stores and proccess information
about employees in the organization for which I work for. However, from time
to time, in the excel sheet I'm working on, the formulae stops working and I
have to enter the data manually. The file has been created from scratch
several times and also I have opened it in other PCs, but nothing works. Why
this could be?

Any help would be appreciated.