Thanks for the repsonse guys...

Today it went to 99.33%

Here's the alert info...

5/16/2013 3:36:32 AM, OS Memory Usage (Percent) on XXX is Warning.

SQL Server instance XXX - The operating system has 99.33% of memory in use.

OS Memory Usage (Percent): Percentage of total memory used on the SQL Server computer.

And there is no linked server on this instance, and CLR is enabled ( not sure if its using CLR )

we are using 64 bit

Available memory Details :

Total_Physical_Memory_In_MB

12277

Available_Physical_Memory_In_MB

12482

System_Memory_State_Desc ( dont know what this means )

Available physical memory is high

Used this query :

SELECT [total_physical_memory_kb] / 1024 AS [Total_Physical_Memory_In_MB]

,[available_page_file_kb] / 1024 AS [Available_Physical_Memory_In_MB]

,[total_page_file_kb] / 1024 AS [Total_Page_File_In_MB]

,[available_page_file_kb] / 1024 AS [Available_Page_File_MB]

,[kernel_paged_pool_kb] / 1024 AS [Kernel_Paged_Pool_MB]

,[kernel_nonpaged_pool_kb] / 1024 AS [Kernel_Nonpaged_Pool_MB]

,[system_memory_state_desc] AS [System_Memory_State_Desc]

FROM [master].[sys].[dm_os_sys_memory]

Please let me know how to proceed...