To solve your video display problem, you will most likely have to install the latest Nvidia drivers avaible at
http://www.nvidia.comAs for your harddisk, if you use a program such as Fdisk, which comes with Windows bootdiskettes, you may be able to delete the partition (If /Fdisk can see it) and create new ones.
Bootdisks are avaible at
http://www.bootdisk.de