Aspire x1700 and BSOD

Hi people,

I have some problems with my computer. Sometimes my computer reboot and I receive this message BSOD -> STOP: 0x000000A5 (0x000100B, 0x50434146, 0xFFD01200, 0x00000000).

One year ago I replace the HDD and all it was good. But some month ago my computer not work correctly and I receive BSOD. I reinstall windows 7 professional but continue equal. I was reading in another forums but i cant to find exactly the same message as mine. My Bios version is R1-B4 (02/32/2009). I found new BIOS in Acer web page but the only version is R1-B3 (it's like a downgrade, isnt?) date 03/23/2009. I dont know if is a good idea to install BIOS R1-B3.