Hiberfil.sys Windows Hibernation Restore File is hidden?

I recently upgraded my RAM from 1Gb to 3Gb. Now i have 2 OS in my Comp.When i logged on to the used OS: 1 , i could see hiberfil.sys - Windows' Hibernation File, that is used to restore ur comp after hibernatin - which is a mammoth 3,135,040 kb in size , thats 3GB.So when i checked out a couple of sites and forums, they all hinted that the hiberfil.sys folder could be seen.But even if i select " shoe hidden files and folders" option in XP, i cannot see it.Is this a trojan or a virus or is something wrong.Please help.I am havin' sleepless nights..seriously...i cannot even defrag that file using Defraggler.It is not getting deleted even after reboot.