Clean installation and partitioning help!

When I had my Toshiba in for repairs, they got it running again but when they put the files, which they had put on an external hard drive, back on they made the operating system partition half the size it was. I don't want to go back to them again as I don't know what they will do this time. I have copied all files on the private partition to an external hard drive of my own leaving an empty partition. I want to give some of that partition back to the os partition. How do I do this without me screwing up too?

Please post back a screenshot of your maximized full Disk mgmt drive map with listings, using Snipping Tool in Start Menu. Then we can advise you correctly.

Tell us what is on each partition and which you want to add to the OS partition.

Found my own answer in a freeware program from MiniTools. Their Partition Wizard Home Ed. 6.0 is a great freeware utility which enabled to resize my partitions. It walked me thru the required procedures. While I didn't need to - I had downloaded quite a bit of the info on both partitiona to an external hard drive for safety sake.

Thanks for offering help, maybe next time I'll need your kind offer.