Format the lot and install Linux...
But seriously for a moment...
I have a 26GB HDD and it is split in the following manner:
Windows 98 - 8GB
Shared partition (FAT32) - 5GB (because Windows won't natively read a Linux ext2 partition)
Linux - 13GB
I use Gnu Parted which is free and will allow you to resize existing partitions without the need for reformatting. I basically have Windows on a Primary partition, the shared space on another, and the Linux stuff in an extended partition (Linux traditionally needs about 3 partitions, /boot; /swap and /)
Ignore all this and install Linux... I use SuSE 7.2
RS