Hi, Many prebuilt systems come with a C drive with all the user space on it and a hidden D drive that has a recovery partition.
Since you are the admin for the system you can make the 2nd partition visible, (google hidden partition) but if you do so then for some makers (e.g. HP) you break the recovery function.
If this is a prebuilt and this is what you are talking about, then definitely make your CDROM/DVDROM backup material and put them in a safe place before messing with the second partition.
If this is not the situation can you say a few words about how the other partitions got on the disk. It very easy to lose data messing with partitions. The more info people have the better the advice they can give. e.g. did you see the other partitions before and not now? What happened between now and the last time you saw them, when did you make the, . etc.