available memory less than 128mb!!! -1 half life 2

Half Life 2 has got some problem on Vista 64 bit, it keeps crashing with a pop up message:
 available memory less than 128mb!!! -1
Solution for this is to run Half Life in Windows XP Compatibility Mode, right click on the short-cut of Half Life, click on the Compatibility tab, select Run this program in compatibility mode for: