Regional settings

Hi,
I have a workbook with a conditional formatting in cel $C$12 e.g. if Cell value is between 0.01 and =C$13-0.01 the pattern turns red.
If someone uses the workbook and enters a new value in C12 but his or here regional settings are different: sDecimal="," and sThousand="." than the conditional formatting isn't working.
How would you solve the problem?

Thanx very much,
Fluppe

Hi,
I think I want to change the regional settings when starting the specific excel file.
[HKEY_CURRENT_USER\Control Panel\International]
sDecimal="."
sThousand=","

It's possible to change the settings when you load the modAccesRegistry.bas in the file.
I have no idea how I can change these settings in VBA and returning the old
settings when the workbook is closed.

Can anybody help me?
Tanx alot!