I have a copy of Siemens Step5 software version 6.3 which suppose to run on DOS operating notebook. The problem is that recently my old notebook crash and I can't repair it. So I install the software in a new notebook running Win98 OS but the Step5 software come with a error saying that it cause an overflow error. I managed to solve the problem. Now, I can open the software but can't use the instruction like transfer (File-PLC, PLC-File, File-File), Edit Block (..in File, in PLC). In fact I only can use the instruction for setting the program file name (Page 1..) and go online (Page 2..). Will it cause by the Win98 OS because everytimes I start the Step5, it call a DOS instruction Append which does not integrate in Win98.