w3wp.exe crash

I have a asp.net 2.0 site running on Win2008 R2 X64, the w3wp process crash these days, create dump files and open in Windbg, I got these message.
Debug session time: Sat Sep 28 16:49:36.000 2013 (UTC + 8:00) System Uptime: 12 days 0:51:25.984 Process Uptime: 0 days 12:53:56.000 ................................................................ ................................................................ ................................................................ ................................................................ .................... Loading unloaded module list . This dump file has an exception of interest stored in it. The stored exception information can be accessed via .ecxr. (5d4.eec): Access violation - code c0000005 (first/second chance not available) eax=0000cc22 ebx=fffff800 ecx=00000058 edx=30244000 esi=30243c44 edi=00000800 eip=74046efb esp=1a86f1bc ebp=1a86f1dc iopl=0 ...