What is decimal separator for you?
For me, decimal separator is comma and list separator is semicolon - so for me works the formula like
Code:
=VALUE(SUBSTITUTE(B2;".";","))
Or you simply select whole datarange, and replace all "." with ",".
About using workbook when having different local settings - so long you have fields with numbers in it formatted as General or Number, decimal separator is adjusted automatically. I.e. when I have a value 1,2 in some cell formatted as General or Number, and someone in US opens the same file, he/she sees 1.2 in same cell. Problems starts with numbers formatted as texts. And in Excel, when you e.g. format the range in text format to General or Number format, all numeric values there remain texts until you don't edit all fields.
In your case, the real solution is not to find some formula to convert values - then you will have problems for users with different local settings. You have to start with reason, why you got numbers which Excel interprets as text. I.e. when you get in range B2 : D2 real numbers instead numeric strings, you don't have to convert anything anymore.