asus p5k going over 45c:(?

hi so my mb temp is at 40-41 just now not doing much at all
when i play a game it gets to 45 and asus probe start screming

any way i like to ask what is the max C
i mean like should i shot down my pc when it hits 45 or can i go higher without worrying about damg to the mb

p.s the cpu seem to be really low staying at 25-30

cpu:6600
mb:asus p5k
ram:corsair xms2 ddr2 800h 1g cl5
psu:corsair 620w hx
and antec 900