Partition Drive C?

Si
1

My laptop has 900gb on drive C and if i want to shrink it i can only use 15gb for new partition, could someone help me?

la

If i want to shrink it i can only use 15gb for new partition

I do not understand. If you want to shrink a partition, you don't need a new partition. You can also zoom out so far that no file "falls out".