I have an older laptop (Sony Vaio VGN-C140G) which I converted from Windows XP to Ubuntu. I had originally installed 12.04, upgraded to 12.10, and am now running 13.04. Under none of these versions has the system recognized my laptop battery. Under previous versions there were /proc/acpi/bat0 files but they all showed no battery present. Now /sys/power does not show any bat0 files. I have been searching the web, and forum, for some time trying to find a solution to this problem but have had no luck. I have seen the DSDT replacement fix around, but it is oudated. The sourceforge page which all of the fixes direct you to download the new DSDT from does not function anymore.
Thank you in advance for any and all help. I will do my best to respond to any questions as fast as possible.