Computer says memory is full need to delete some files but nothing is showing up on my screen i cannot see any of my files or photos after login. computer also goes quiet can someone help?

Hi, when i log on to my computer (2009 mac book) i get a message saying memory almost full please delete some files. however after typing in the login details the computer goes silent and i only see the standard mac background with none of my icons, files or photos and the computer stops spooling and seems to have shut down. i cannot seem to access any of my files and i have repeatedly turned my computer on and off. also i have a timemachine so i tried on another mac and pc to see if it backed up my material from the computer which is not working. however, the files seem to be in a format i cannot open on the other mac and the iphotos and my personal movies in quick time cannot be open as the computer as the computer says that there is either a format issue or the iphotos are a back up and therefore cannot be opened in the library`? how can i access my material from both my computer and the timemachine? many thanks