I got a problem with Ubuntu 18.04. It has worked fine all the time, until I had to change the ventilation fan of the desktop. Since I changed the fan, and used spray duster on the CPU and the other parts of the mother board, I get the following message at start-up which stops the system:
attempt to read or write outside of disk hd0 ubuntu
press any key to continue....
There is no chance to do any of the maneuvers that are described in other similar posts here on StackExchange, and therefore I cannot really do anything with it. However, if I restart again and again, at a certain stage, this warning does not appear and the system boots normally.
Is there some way to work around this occasionally appearing problem, or should I just continue as it is, and restart and restart over and over again till it works?
UPDATE #1 after corrections by heynnema.
All disks converted to GPT table. Reinstalled Ubuntu 18.10, but it doesn't start. All I get is the startup animation of the Ubuntu dots that flash from left to right, without any color in the background or anything happening. Inserting snapshot:
Another restart brings the regular Ubuntu background forth, but as the previous case, it just flashes its process lights from left to right. Nothing happens, the system does not start. What can I do? Should I go over to another table structure?
UPDATE #2: Updated the BIOS to most recent version. Tried to reinstall Ubuntu by erasing the disk and use LVM set up. Installation stopped when entering the LVM menu to make a boot table. Nothing happens, no buttons work. Before LIVD CD starts fully, it shows a dark screen with white text:
APEI cannot start mem [342423e4dxxx..] or something
the Ubuntu Trial starts then on Live CD and when trying to format the boot drive from LIVE CD In Gparted, the option to format are hidden and cannot be used. Entering Install setup and then at Install options selecting again "Erase Disk and install Ubuntu", it now says:
The computer has not detected operating systems
Installation runs ahead.
Installation failed again. Same screen as depicted above in the image.