this has happened to me before... options. try importing the file into a new sketchup file via the import menu. try opening the file before bed and giving it some 8 hours to attempt to open... making sure not to use any other software and don't let the screensaver interrupt. try importing the file into another program such as 3DsimEdit or 3Dmax some of these have sketchup file import and some are plugins that allow it. then export it again back to sketchup. rebuild the whole model from scratch and employ the make backup option as well as autosave. you might try sending the file to someone else and see if they can open it, "fix problems" and "purge" for you.