i have problem with my hard disk partition it is 37.2 g.b.
& it is 27.2 g.b. full but when i try to store file via copy pest
it says not enough disk space
but when i install here it successfully stored

this partition is made by merging of 2 drive

it is larger drive in my computer & data is important so i cannot format it
what can i do ?

From what i understand what you written here its that you dont have the permission to write to that drive (i dont understand why).
You can try to reinstall your windows, but then select the WHOLE drive as ONE partition.

If anyone here has any other suggestions for solving this, please post, because a reinstall all i can think about, about solving the problem.

Could you post a screenshot of your "My Computer" window so we can see what is going on.

Also, post a screenshot of "Control Panel > Administrative Tools > Computer Management -----> Disk Management" so we can see what is going on there too.