Changing dots to commas

I need to be able to make sums in a report that I'm creating out of data that I collect from a "query" on a website.

The query displays numbers as 1.000,00 and my computer settings are 1,000.00 (and have to stay that way otherwise some of the programmes on my computer won't work).

I have already tried to go to Tools, Options, International and unticked the use system separators and that doesn't work.

I can't manually change each cell - it's to much data for that and the information is to sensitive to risk making an error.

It's driving me nuts... does anyone give any tips of what to do which is relatively quick and limits the risk of making a mistake.

Hi & thanks. Sorry if this is a stupid question but where do I write that command or formula or whatever you call it?

On the same worksheet as the cell in which you want to replace the "dot", put the formula in an adjacent column.

Example:
If your data are in column-A starting at cell A1, then copy and paste the formula into cell B1 or any other empty column on row 1. Then click the formula cell once and drag the fill handle to fill all cells below.