Thanx for support but i cant remove that pc any other solution?

if you have antivirus then do a full scan on the pc..

its done already

You might want to clarify the question, so we don’t need to assume what the problem is. Also, let us know what troubleshooting steps you have taken so far, so we don’t suggest things you have already tried.

If a machine is generating spam, then you should disconnect it from the netowork and scan it for malware. If you already did it, then do it again with another anti-malware program.

For better results you should install and update the anti-malware program of your choice, then restart the machine in safe mode without networking, and then do the full scan.

Please read my suggestion above about blocking port 25 outbound at your network edge. This will help keep your network off blackhole lists.

Assuming this is a Windows machine: (if not please provide additional details about system config)
You can run netstat -no at a command prompt on this machine to see what process (PID) is connecting to port 25 on a remote system. Once you get the PID number, run tasklist at the command prompt also to get the name of the process connected to port 25.

For example the following shows how to find out the process connected to a remote system on port 5900 (VNC)

netstat -no

Active Connections

  Proto  Local Address          Foreign Address        State           PID
  TCP    10.11.50.33:445        10.11.99.11:1064       ESTABLISHED     4
  TCP    10.11.50.33:5441       10.11.99.11:445        ESTABLISHED     4
  TCP    10.11.50.33:5617       10.11.18.2:5900        ESTABLISHED     3544
  TCP    127.0.0.1:60164        127.0.0.1:60165        ESTABLISHED     5532
  TCP    127.0.0.1:60165        127.0.0.1:60164        ESTABLISHED     5532
  TCP    127.0.0.1:60166        127.0.0.1:60167        ESTABLISHED     5532
  TCP    127.0.0.1:60167        127.0.0.1:60166        ESTABLISHED     5532

tasklist | find "3544"
vncviewer.exe                 3544 Console                    1      8,676 K