Do as a previous poster in that you open a drive window either from the HD or the Finder icon in DOCK (not the menu bar). I setup computers the way a customer would like it by clicking the Finder icon in Dock first and setting its position, size and view by (icon, list or column, I prefer...
Clear out cache files in You>Library/Caches these are all temporary files and can be cleared with no affect. Also in the Applications>Utilities folder is Disk Utility. Launch it and click on the name or size of the Hard drive on the left and at the left lower corner of the main window click on...