Various BSOD

Hi, in these days appear various BSOD on my pc. Most of them are "Irql_not_less_or_equal", but there are "Memory_Managment" too. One year ago I had the same problem, but updating all the drivers and the bios the problem didn't reappear. I try again in this way but dosen't work. Attached are the last two BSOD.
Any help or guidance would be greatly appreciated
Thanks

here the files

my system is

windows 7 professional x64
Intel i7 920
Motherboard asus p6t- se
3x 2gb DDR3-1066
Ati radeon hd 4800