I recently upgraded my PC. New 120gb hd and cd-rom rw. Everything was working fine until I changed the battery in the mother board. Now my BIOS will not detect the cd-rom drive when I run the start up disk.

Hello, When you installed your cd-rw, did you check to make sure it was properly jumpered? If it is on a cable by itself, it has to be jumpered as "Master". If it is on the same cable as another device, one device has to be "Master" & another has to be "slave". For example: If you have a cd-rom and a cd-rw on your computer attached to the same IDE cable, set the cd-rom to master and the cd-rw to slave. Also, make sure that the cables are in tight. I hope this information is of some use to you. Good luck, ~winipcfg

When you changed the CMOS battery, the BIOS was rest to its factory defaults negatting changes your added hardware made in the BIOS setup. I guess that is the reason for your CD-RW not being recognized by the BIOS and consequently Windows. The question then would be how come the 120GB HDD installed at the same time was working OK? I suspect that the configuration was something like this: The 120GB HDD might have replaced the original HDD as Master in the Primary IDE channel while the new CD-RW might have been installed on the Seconadry IDE channel made to Auto-detect the new IDE device for the first time (probably not in factory defaults) [either as Master or Slave] I would suggest you to access the BIOS setup and make the particular IDE Master or Slave to Auto -detect and Save settings and Exit If this fails, open and recheck all cables and Jumper settings for proper installation. Since it worked before and if no one has opened the case, I suspect this possibility to be less likely unless an unfortunate primary failure of the CD-RW might have happened in which case replacement of the drive is the only option.