I get a report from europe with date format 13-01-2012 00:00:00 . I tried simply formmating it to US format, but it only applies it to the first 12 days of each month. All help is greatly appreciated.
And I suspect that those dates are not what you would expect, if you examine them closely.
In other words, Excel may convert 12-01-2012 but it will turn out to be 1-Dec-2012 and not 12-Jan-2012.
I have assumed, in the above, that your Windows Regional Settings have a US date format mm/dd/yyyy
One solution will be to IMPORT the file using the Get External DAta / From Text option on the Data ribbon.
This will bring up the Text wizard which will allow you to enter the format for the dates as DMY. You will probably have to split out the time portion.