Wrong Screen resolution - lost use of monitor even on rebooting

[newtusmaximus]

The reason for the problem not identified, even after all the kind efforts of colleagues here on the forum.

HOWEVER, once back  via nomodeset modified grub onto 640x480 resolution I thought I would run menu/settings/install drivers to see what came up, even though I was not aware of any proprietary drivers - there hadn't been in LL2.8 32bit when used on this setup before I had upgraded the RAM .

Behold: some Intel microcode CPU drivers were identified as being available so I loaded them AND  afterwards ran menu/favourites/install updates but No immediate change to screen resolution.  So rebooted via menu.

Switched off monitor again until boot up activity had settled, switched on monitor and logged in -
RESULT - high resolution screen!!
menu/settings/display showed original iiyama North America 18 inch monitor identified and resolution at 1024x768 x 60Hz.

Updated Hz to 75 without problems - BUT LEFT RESOLUTION ALONE!!!  did not want to fall off the cliff again.

So problem gone away but can't say it has been resolved,  as far from sure what action overcame the problem.

HP-Compaq-dc7700p-Ultra-slim-Desktop:~$ xrandr
Screen 0: minimum 8 x 8, current 1024 x 768, maximum 32767 x 32767
VGA1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 360mm x 290mm
  1600x1200    75.00 
  1280x1024    75.02 
  1152x864      75.00 
  1024x768      75.08*  70.07    60.00 
  832x624      74.55 
  800x600      72.19    75.00    60.32    56.25 
  640x480      75.00    72.81    66.67    60.00 
  720x400      70.08 
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

Suppose I should try and change screen resolution to higher to see whether I can recreate the problem, or it has in fact gone away for good., BUT forgive me if I chicken out of this.  This pc is my main workhorse, and I use the large CRT iiyama as it is a treat to use.; even if a bit quirky.

Again thanks to  Bitsnpcs  and firenice03 for all their good will and effort in support.  Much appreciated.  Shows the spirit of this forum!!