Unless you want to format the one drive, there should be no reason to make it visible. The only way you would be able to format it if it is not letting you through the OS would be to boot to your OS install disc, and format from there. But then to make it one partition, you may have to format the active partition as well, which would be the same as reloading your operating system.
Otherwise you can try going into the cmd prompt and forcing a format through there. Post back with WHAT you want to do to that partition, and we'll be able to help you more.
CPU - AMD Phenom X4 9500 2.2 GHZ
Motherboard - MSI MS-7374
Chipset - nVidia nForce 750a Sli
RAM - 6GB PC2-6400
Video Card - NVIDIA GeForce 8800 GTS