phenix,
The questions you were asked are because quite often what you are seeing is because of a drive with very little free space available, which doesn't appear to be the case here.
Download, install and run CCleaner (link in my sig). Run the cleaner portion thereof.
After that, then carry out following:
LIST OF STARTUP PROGRAMS USING CCLEANER
CCleaner | Tasks icon | Startup tab | click on Save to text file button (bottom right side)
Using the PAPER CLIP icon in the top panel of a Message Reply window, attach the .txt file generated by CCleaner.