depends on how you try to do this.
you can try using a linux livecd and copy the data on the partitions to a FAT32 or VFAT partition, thus making it readable for just about any os (incl. windows)
you will most likely never be able to read your linux partition with a windows system, so you will have to use linux for this anyway you look at it.
if you do not have a livecd just do a minimal install and copy the files to your fat partition (cp original target -R -v)
so if you want to copy /data to /fat you will have to do cp /data /fat
the recursive (-R) will copy all files in the subdirectory., the verbose will simply show you what he is doing.
be sure to check your copy command BEFORE you press enter, cuz he will simply copy everything that you ordered it to copy.