On one particular machine, in Excel, any number typed into a worksheet is
automatically converted to a decimal (ie 10 changes to 0.1, 20 changes to
0.2). Have checked all formatting options and they are all OK, have tried
deleting the blank template, and still the problem re-appears.

Has anyone come across this before, could it be a small virus, or just
another bug in the system.

Any help is really appriciated.