vista partition saying 66mb when i have 70gb free?

It's because there are two different ways to display space on the hard drive.

When they say you have 70 GB free they mean

70 x 1000 x 1000 x 1000 Bytes

When they say you have 66 GB free they mean

66 x 1024 x 1024 x 1024 Bytes

This is because a simple count of the bytes is 70 billion

But the bytes are all allocated by the operating system in units that are 4,096 bytes in size (or 8,192 or 16,384 depending on the size of the hard drive). If we report the byte count with that restriction then there are only 66 GB.

This odd way of calculating occurred many years ago because memory is measured in powers of 2, and 2 ^ 10 = 1024, and that number is close to 1000, so the industry got lazy and called it 1 kilobyte, because 1000 = 1 kilo. The industry is trying to create a new term - GiB, where data space that is called 70 GB would be called 66 GiB.