Microsoft has won agreement with PC makers to add a fundamental change at the BIOS level to improve security in Windows Vista. The software giants Address Space Layout Randomization (ASLR) feature could make automated, large-scale attacks significantly more difficult. ASLR involves arranging the positions of certain data areas, such as the position of libraries, heap and stack, randomly in a process address space. Certain types of attacks, which rely on these components having predictable target addresses, thus have a low chance of success when ASLR is in place.”]
Source: https://www.csoonline.com/article/2120753/microsoft-to-modify-bios-to-make-vista-more-secure.html