Please help

I got problem on my Window 2000 pro. Reinstalled last week /SP4 and some regular software. It works fine for about few days and start to get blue screen 4 times today. I used WinDBG and found these in Dump file:
Executable search path is: Can someone Prof help? Thanks in advance.


*********************************************************************
* Symbols can not be loaded because symbol path is not initialized. *
* *
* The Symbol Path can be set by: *
* using the _NT_SYMBOL_PATH environment variable. *
* using the -y argument when starting the debugger. *
* using .sympath and .sympath+ *
*********************************************************************
Unable to load image ntoskrnl.exe, Win32 error 0n2
*** WARNING: Unable to verify timestamp for ntoskrnl.exe
*** ERROR: Module load completed but symbols could not be loaded for ntoskrnl.exe
Windows 2000 Kernel Version 2195 (Service Pack 4) UP Free x86 compatible
Kernel base = 0x80400000 PsLoadedModuleList = 0x8046e1b8
Debug session time: Mon May 7 17:20:54.065 2007 (GMT-7)
System Uptime: not available
*********************************************************************
* Symbols can not be loaded because symbol path is not initialized. *
* *
* The Symbol Path can be set by: *
* using the _NT_SYMBOL_PATH environment variable. *
* using the -y argument when starting the debugger. *
* using .sympath and .sympath+ *
*********************************************************************
WaitForEvent failed