If you are re-installing the game to the same path, it should not be taking up any additional hard drive space each time, and even installing it to a different path, the previous one should have been deleted. Try running ScanDisk and see if it is just an error in the free space listed (FAT32 in win 98/ME is particularly susceptible to this), or if there actually is more space used. The saved game folders are fairly large, as well, as additional saves will take up more room.