monitor malfunction

[V70grey]

I am old guy new to computers.  I have an 18 month old PC with "Proview" monitor.  Just last night wjen I switched on the monitor/computer the monitor stayed on for only 2 seconds and switched off.  I repeated the on/off routine 10/15 times and eventually the monitor stayed on.  This morning the process repeated.  I noticed however, that just before it switched itself off each time it was very dull.  When at last the colour came up fully, the monitor stayed on.  What might be the problem?

[Deerpark]

Sounds like the monitor is dying but check the monitor plug for any bent pins just.
If the plug is fine you should try the monitor on another computer just to make sure it is  the monitor.