First thing you should do is to not to do something which results in writing to your harddisk. Although its unavoidable , but keep it to minimum. Download any undelete software from download.com or snapfiles.com and run it. it will list the deleted files on your system.
http://www.officerecovery.com/freeundelete/
may be this will help.
P.S. dont forget to check your recycle bin first.