This question already has an answer here:
I got and installed Steam a few months ago in my system drive. And then I got a backup of Dota 2 and installed it. It was fine till a month ago before my lap top got broken.
With passing problems and finally getting my new pc and recovering a small amount of my past laptop data I found out that my Steam client has been removed.
Now the problem is that I have my Dota game folder (it's not the backup file) but I don't have my Steam client and I should reinstall it.
After that am I gonna be able to play Dota again? Or should I download it from the beginning?
It may not be an important thing in developed countries but in mine it is. 12GB is a huge amount for downloading!