Suddenly downloaded .xls opening with numbers as text

HI I never had this problem before using Excel 2007, but suddenly its doing the following every time I download a .xls report it opens it up and all the numbers are stored as text and I need to do a conversion on them which really wastes time.
I have checked my settings and un-ticked use system separators and left the following as the settings
Decimal Settings = .
Thousand separator = ,
With the hope that this would work - is there something I am missing ?
Please help this is driving me crazy and slowing me down

Thanks
Mike