Steam won't recognize Path of Exile files, neither will the seperate client

Built a new computer today and I mean to transfer over my PoE files from one harddrive to the other.

I have tried every single method to get steam to recognize the PoE files and not attempt to redownload everything.

I have used the backup and restore method for other games, which have worked fine for some. It hasn't worked for PoE, steam won't recognize the backed up files because PoE doesn't show up on my library.

I am running on 4 gigabytes of data a month, I cannot afford to redownload PoE again.

Any help is appreciated, let me know if I have missed anything out.

Thankyou

Initiate the download for steam, let it run for 1% then stop...go into the steam folder and then into steam apps, and then into the downloading folder, delete the ggpk file there and replace it with your original ggpk file and resume the download...it should just complete