One way to find out is to close all browsers , msn etc then open a command prompt.
go to start > run > cmd > enter.
Then in the window that opens type
netstat -ano and enter.
If you see " established " anywhere then your computer may be hacked.
To shut down the " established " program,make a note of the pid number. Then press control > alt > delete at the same time to open Task Manager.
Select "processes " then "view" then " coloumns ".
Tick the box for Pid (process identifier) and OK.
You can then find the pid number and close the program that is running.
Hope this is helpfull for some of you.