[Q] unable to delete Delta Rom folder from internal SDcard topic

i just got an s3 from my friend ..so i dont have detailed knowledge about the roms and other things of s3 ...
i found a folder named DeltaROm ...(my friend might have installed this rom before ..)
i am unable to delete the folder ...i tried deleting it from my pc (s3 connected to pc) but after 1 or 2 minutes ..delta rom folder appeared again ..
it is occupying 450+ mb in internal storage ...and same amount of storage in /0 folder ..
so any one had this problem ...how to permanently remove it from storage ...