Hi, I recently installed a PC in a commercial vehicle. It has a 24V battery backup system to give continuous power, however at some point the CMOS lost its contents and the BIOS defaults were (automatically) loaded. The RTC was also reset. The 3V CMOS memory backup battery seems fine, and it seems impossible that it could have become disconnected due to vibration. I'm thinking that the memory corruption could be due to either: 1) PC board input power spikes (unlikely) or 2) Software problems. As it is possible to write to the CMOS using software, could Windows 98 (which the thing is running) have done so? Can CMOS be corrupted due to power supply problems? Any ideas or experience? John ----------------------------------------------- John Lawton Electronics Custom Electronics Design & Development design@jle.co.uk http://www.jle.co.uk ----------------------------------------------- -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body