Vista - Harddrive space why i have 4 drives

one is OS,
two is Recovery,
third is Datapart.
four is laptop (\\GAMER)

Now wen i install programs, games etc onto computer it auto installs onto OS
drive, which od course is filling up pretty fast.
id like to clear the Recovery drive to make more space, can u tell me wat
the Datadrive is for?

im using Vista Home Prem pre-installed onto Dell Laptop.

and is there a way to transfer programs onto Datadrive without un-installing
them all first and will they still run prperly as the Laptop is running oh
so slightly slower. Just one other thing if u can help wen i copied a prog
over to Datadrive, it also appeared on laptop\\gamer drive to..

cheers
Dimaggio