the program was existed here C:\Program Files (x86)\PCData\minerd.exe but I deleted it now , I want to know what was that program ?
As hinted already it is a bitcoin miner.
I've not much experience with bitcoins, however enough to say it is a Peer to Peer (P2P) based system, where your (and most other user's having the bitcoin client running) computers are used for solving the transactions.
You can consider you computer running as a server (or gateway) for some other peers, and this can easily become a resource insensitive task.
Deleting it is safe if you don't intend using it often (You would better kill the app from task manager after using it, or find system tray icon and close it from there)