I am working on an Acer Aspire 1810. Part # 91.AB610.D02. I am attempting to upgrade it to Win 98. I have FDisk and formatted without apparent problems, but it will not let me install the new OS. I keep getting an MS-DOS extender error. I am loading from a FAT32 boot disk that I created with a generic cyberdrive CD Driver. It is working fine and therefore I am not loading DOS. Why the DOS error? Does Acer keep hidden files on the drive that are not removed during format?? If so is there a DOS command or a program to completely clean an ACER drive and install the OS without using the ACER Recovery CD???