[lubuntu] LXLE 16.04 issues

G'day,
I have used LXLE 14.04 for a year or so with no problems and installed 16.04 as it was another LTS and have a couple of nagging problems.
1/ if I select LXLE 16.04 from the grub menu the computer boots to a desktop, no worries but if I let Grub time out the computer goes through the process of booting and makes a Fanfare noise but the screen is black and unresponsive.
2/ my screen save is causing a problem in as much as if the machine is unattended and the screen save kicks in moving the mouse of pressing enter results in a Garbled image with a big red button which means a re-boot is required.
3/ I have my addresses on a USB stick but permission to read it is denied si I need to edit permissions to R/W

If anyone can please help me to get the machine going I will be very grateful as 16.04 looks like being a solid, fast OS
regards Joe.