Question : Problem: I deleted a folder by wrong from my exteranl network hard disk

actually, I deleted a shard folder by wrong from my exteranl hard disk which is working as a node in the network, I didn't make any backup before.

my hard disk is WD?

what to do?

Answer : Problem: I deleted a folder by wrong from my exteranl network hard disk

Try GetDataBack http://www.runtime.org/  Free to try.  If it sees the missing files you pay for full functionality.

Also look at PCInspector http://www.pcinspector.de/file_recovery/UK/welcome.htm and Recuva http://www.recuva.com/

Both are free.

I'd try GetDataBack.  If it sees your files then try the free ones.  If they work you save money.