LG L1900R - when connecting the analog prt it runs into ANALOG SAVING MODE, What can I do? (already changed the cable... )

try changing your resolution to a smaller one

The resolution should be set to 1440 x 900 or 1280 x 1024, the refresh rate should be set to 60.

try those settings above

also try this:
Go the desktop, right click with mouse and select properties (if it XP) then it will open Display properties --> there you need to go to Screen saver and then to power option

Disable any power off mode on/ Sleep mode.