Storage space

[T-santi8]

I have a hp pavilion 15-cs0064st product number 4AG15UA, that has a 1TB hdd but when I look at storage settings it says I only have 75.9gb of storage capacity?

[TheOldMan]

Open "Computer Management"

Under that title you should see a section titled "Storage" and a subject under that as "Disk Management"

Open Disk Management.  When that screen opens, there should be a complete listing of all the "drives" present in the system, and the capacities.

Post a screen-shot of that screen.

[T-santi8]

I opened computer management and disk management and it shows 839.32GB to be Unallocated.

[TheOldMan]

If the unallocated space is adjacent to the rest of the system used space, then perhaps disk management can assign or merge the  unallocated  space with the rest of the system space.

Here is a thread sharing info about that subject

https://answers.microsoft.com/en-us/windows/forum/all/merging-three-unallocated-partitions-into-one/...

It might be easier to use a third party software for that task.  If you need further help, try this

https://www.partitionwizard.com/resizepartition/how-to-merge-unallocated-spaces.html