a few days ago, i havent any problem but now I cant use file and printer sharing on the windows 7 but everyone on the network can. maybe I install some program that make this change or disable a windows services! (Like: proxifier, ...) Now: -I can ping everyone on the network. -everyone can ping me. -I cant see their computers in windows 7 "Networks" So, I cant use file and printer sharing. -everyone can see my computer in windows 7 "Networks" and also can use my file and printer sharing. -with a LAN messenger program, we(I & everyone) can text chat, video chat and transfer file. . . I want see another computer on the network and use windows 7 file and printer sharing!!!