Display stuck @640 x 480 following LL installation: how do I fix it?

[m654321]

A few hours later: just worked out why I couldn't boot from the LL installation DVD on the Packard-Bell laptop: it wasn't enough to just select CD/DVD from the Boot settings, but I had to 'physically' move it to the top of the boot-order list, using the '+' character key. So I reinstalled LL 3.8 (this time 64-bit) and everything went very well.

But: I still have a display resolution problem. During the LL installation process, the screen resolution appeared normal, but on reboot following installation, the resolution is stuck (once more) at 640 x 480 with no other choices apparent in the Display settings, as shown in the screenshot in post #1 above, and in terminal output here:
 

Code:

mike@EasyNote-MX37:~$ sudo xrandr
[sudo] password for mike:
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 640 x 480, current 640 x 480, maximum 640 x 480
default connected 640x480+0+0 0mm x 0mm
   640x480 73.00* 

This problem has been reported elsewhere: https://forums.linuxmint.com/viewtopic.php?t=228989
However, the following two solutions proposed in this link didn't work, i.e:
changing this line:

Code:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to either

Code:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash ACPI=off"

or

Code:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash "xforcevesa""

To provide further information, inxi output from terminal is as follows:

Code:

mike@EasyNote-MX37:~$ inxi -Fzx
System:    Host: EasyNote-MX37 Kernel: 4.4.0-160-generic x86_64 (64 bit gcc: 5.4.0)
           Desktop: Xfce 4.12.3 (Gtk 2.24.28) Distro: Ubuntu 16.04 xenial
Machine:   System: Packard Bell BV product: EasyNote_MX37 v: PC10E00401
           Mobo: PACKARD BELL BV model: T12C v: 1.0
           Bios: American Megatrends v: 207 date: 10/11/2007
CPU:       Dual core Intel Pentium Dual T2310 (-MCP-) cache: 1024 KB
           flags: (lm nx sse sse2 sse3 ssse3) bmips: 5864
           clock speeds: max: 1467 MHz 1: 1067 MHz 2: 1467 MHz
Graphics:  Card: Silicon Integrated Systems [SiS] 771/671 PCIE VGA Display Adapter
           bus-ID: 01:00.0
           Display Server: X.Org 1.18.4 drivers: fbdev (unloaded: vesa)
Resolution: [email protected]
           GLX Renderer: llvmpipe (LLVM 6.0, 128 bits)
           GLX Version: 3.0 Mesa 18.0.5 Direct Rendering: Yes
Audio:     Card Silicon Integrated Systems [SiS] Azalia Audio Controller
           driver: snd_hda_intel bus-ID: 00:0f.0
           Sound: Advanced Linux Sound Architecture v: k4.4.0-160-generic
Network:   Card-1: Silicon Integrated Systems [SiS] 191 Gigabit Ethernet Adapter
           driver: sis190 v: 1.4 port: cc00 bus-ID: 00:04.0
           IF: enp0s4 state: down mac: <filter>
           Card-2: Qualcomm Atheros AR242x / AR542x Wireless Network Adapter (PCI-Express)
           driver: ath5k bus-ID: 02:00.0
           IF: wlp2s0 state: up mac: <filter>
Drives:    HDD Total Size: 250.1GB (2.2% used)
           ID-1: /dev/sda model: Samsung_SSD_850 size: 250.1GB temp: 0C
Partition: ID-1: / size: 23G used: 5.2G (24%) fs: ext4 dev: /dev/sda2
RAID:      No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors:   System Temperatures: cpu: 58.0C mobo: N/A
           Fan Speeds (in rpm): cpu: N/A
Info: Processes: 171 Uptime: 4 min Memory: 576.6/1873.4MB
           Init: systemd runlevel: 5 Gcc sys: 5.4.0
           Client: Shell (bash 4.3.481) inxi: 2.2.35