Hard drive format

I am fairly new to NT4 and have always worked with server HD sizes in Mb’s. Where I work have now ordered a new data server with a 75Gb HD. When I tried previously to partition and format an 8Gb HD with a partition greater than 3.9Gb it would not format and I had to stick to under 4Gb.
I have tried both NTFS & Fat16 but with same results. Obviously I can’t set a 75Gb to such small sizes. I am looking at c to 4Gb, D to 20Gb both set to NTFS & the rest as FAT16 for open storage of user programs.Grateful for any help in my lack of knowledge for up-to-date setups. Thanks.