Q: I AM USING WINDOWS VISTA ULTIMATE 32-bit OS!!
A: You don't say what operating system you use or if it is a new drive you are installing. You can only do this splitting (also known as partitioning) whilst there is no data on it or all will be lost. Some third party software is available like Partition Magic which could split the drive if it has data already on it but be very careful. Back up any data first... If it is XP you can split the drive (also known as partitioning) using the disk management tool. Right click "my computer" icon - choose manage from the menu. Left click disk management in the left pane. Locate your new drive in the lower section of the right hand pane. Right click it and choose create partition. There should be an option to choose how much of the drive to use. If it is a new 250gb drive and you want to create two equal sections divide the value by 2 and enter it in the size box. Repeat this for the other half of the drive leaving the suggested size in the box. Once this is complete you can format the drives. Right click on one of them and choose format. Once complete repaeat for the other partitions. Hope this helps.