I forgot to mention this earlier. We have 4 computers in the lab and it freezes on 3 of the computers and not on 1 computer. This 1 computer is the place where I originally created the program and copied the program to the other 3 computers. I deleted teh data of the program from this computer before transferring to the other computers and also recopied the entire program again yesterday to the other 3 computers. Still the same problem is happening. Also another thing I noted is that the 3 freezing computers have a VOICE Folder in the data folder ? I have never asked directRT to record voices so i dont know if this is part of the problem. No voice data is recorded in the computer that works fine. Hence, please reply as early as possible I am trying to get this fixed asap so I can run my experiment smoothly and efficiently.