Partition questions-Inspiron 8200

I recently acquired an Inspiron 8200, with two new hard drives. Windows XP-SP2 on the main drive, no data added yet.  The second drive had already been divided into two partitions, 19GB and 92GB, no data added yet.  I don't know why, but the Temporary Internet Files Folder has been re-directed into this 19GB partition, which is named Backup.  Does this serve any good purposes,  and how could I get this drive back to one partition, and how can I get the temp. folder back into its normal place?  There is a shortcut to this temp. folder, in the My Recent Documents folder, on the maim drive. I back up everything on an external drive. 

Also, would it be a good idea to partition the operating system on the main drive?  If so, why, and how would I do it?  It takes up only about 3GB of space, so how large would you make the partition?

 

Thanks