It can be called as a known fact, Windows on Acer's laptops stops working when the battery becomes weak. Nobody knows why, but the keyboard and the touchpad do not respond at all.
A solution for that - boot windows with removed battery and disable ACPI driver.
Also, acers have a hidden recovery partition, which should be accessible on Alt-F10 combination after the POST has done its job. But if the MBR record is overwritten, it's no longer there.
One can carefully restore the sector, it's template is located in a hidden partition's file (/ACER/TOOLS/RTMBR.bin). The file does not contains the partition table, so it should be taken from the existing MBR sector (back up it anyway).