Ok, transfer the contents from C: to D: drive if you have enough available free space.. If not, try to compress contents on drive D: to gain some extra space.. If you can't do that, that's probably because D: drive is formated with FAT32 file system, in that case you should convert your partition to NTFS.. Now you can boot from CD and then delete partitions C: and F: You can install windows on C: partition.. When windows installation finishes you can use disk manager to convert your drive letters as you like or recreate partitions.. You also can use some third party software like Partition Magic 8.0..