Help - Can’t restore P3 to a new computer

Dear all - need your kind help...
I just got a new laptop from the company that had P3 v3.1 installed. I tried to restore the compressed backup file from the old computer to the new one, and it seemed the backups could be extracted to all P3 files with no problem.
But when I tried to open it from the folder as usual, it just couldn’t find the project! how come the "open a project" window was blank while the P3 files are all right there in the folder?? Any help or suggestions?

Thanks in advance!