Without knowing what type of raster file format (other than it being an integer grid) this is, no way to know for sure which GIS applications are capable of reading it.
GDAL (an open source raster data swiss army knife) has a command line utility program called "gdalinfo" that will display a lot of information about most kinds of raster data files. Using gdalinfo to examine your file might be your best bet in figuring out what format raster data you have.
There is a windows installer package for "FWTools" that contains a prebuilt copy of GDAL. You can get it here:
The FWTools package also comes with an application called "OpenEV" that can display any of the raster formats that GDAL understands.