If its a new hard disk or you want to reinstall an operating system then it is very good practice to fdisk and then format the hard disk in question. To fdisk, you usually need to have a boot disk and run that from there. When the fdisk is done,i.e. the dos partition has been set, then you can proceed to formatting the hard disk.
After this has been done, install operating system and then a partition program to create partitions if you have a large hard disk as windows partition creator is useless. I recommend Powerquest Partition Magic 8 for this. Once this is done, you are free to install other programs to these partitions. Just as a word of advice though....try to install other programs to partitions other than c and this will ensure the operating system works reasonably quickly.
Good Luck.
CJ
CJ, March 2007