1. Update putty X11 settings. Click the "ENABLE X11 FORWARDING", for each putty connection.
2. Login to unix server.
3. Run > xauth list
Output will be something like
Where nn is a number like 10, 11, 12, ...
4. Start exceed / similar server.
5. Run > export DISPLAY=localhost:nn
If sudoing to another unix account then run the following:
1. Sudo to unix account
2. Run > xauth add unix:nn ... Output from xauth list command ran in step 3 above.
3. Run > export DISPLAY=localhost:nn
Now run your x11 application.