Formatting datetime or extracting datetime from a text value

Hello,
I imported a .txt file into excel. It has a datetime value (eg:18-05-2013 09:16:22 PM) which has is formatted as general. I want to convert this to a proper datetime format so that I can use this to find the difference from another datetime value.
How do I do this ? I tried Datevalue but it doesn't help. I also tried to split this into date and time separately using LEFT and RIGHT functions but the results are still in text and I cannot use this to subtract from the other date.
Best solution will be if there is a way to convert this to a datetime value that can be then subtracted from another date time value that will give me the hours or days and hours between them.

Thanks
Alex

Nick's picture

if you select the column, go

if you select the column, go Data =>text to columns => finish

Does Excel then understand all the dates ?