Be careful, if you didn't partition the drive yourself, then the D: drive might be a recovery partition. It is usual that some manufacturers will format your C: drive as NTFS, but the recovery drive as FAT32.
What size are each of the patitions? The recovery drive (D:) will usually be considerably smaller (with very little free space) than the main drive. The recovery drive will usually be less than 10GB in size.
I assume we are talking of one partitioned drive here, and not two separate discs. If just the one with two partitions some info as to the partition size could ascertain whether one is a recovery partition or not, but it does sound like it. Is this how things were when you got the machine? If the fat32 drive is for recovery you should not be using it for anything at all.
My compter right click - manage - storage - disk management
If two disks will show as Disk0 and disk1 if one drive you will seeit as disk0 and split into two partition on that disk.
DO NOT mess with partitions or file systems if your drives contain recvery data.
If you are using Windows XP, it's a good idea to convert your system drive to the NTFS file system if you have not already. In addition to providing numerous security and data recovery improvements over FAT32 (the file system of choice for Windows 9x/ME and XP Home) it can also speed up your system slightly.
In fact, the only real reason for sticking with the FAT32 file system for any of your data is if you have more than one operating system on your PC and the other OS's can only see FAT32 partitions (as would be the case with Windows 98, for example, which is incapable of reading NTFS data).
To convert your drives to NTFS: Right click on 'my computer' and select 'manage' From the computer management window, expand storage and select 'disk management.' Using the 'file system' column of the upper pane of this window, you can easily check what file system each of your logical drives is using. Make a note of this information. Now open a command prompt window by going to 'start\run' and typing 'cmd' To convert a disk to NTFS, type 'convert (drive letter): /fs:ntfs' So for example, if you were going to convert your C: drive, you would type 'Convert c: /fs:ntfs' at the prompt.