My server was eating up lot of physical memory and was crashing due to shortage of RAM . I was not able to resolve the issue for 2 days but file I came to know about a utility called RamMap from Microsoft , which I ran on my server. It revealed that metafile consuming the highest amount of RAM.
High memory uses by metafile on Server 2008 R2 can be reduced using an another Microsoft called CacheSet which can be downloaded from here :http://technet.microsoft.com/en-us/sysinternals/bb897561.aspx
More info about metafile : What is metafile? and different types of files which consume the physical memory on Windows Server.