My monitor shows a black screen

Pc was running, then house power goes off. After starting when power comes, it shows blue screen then monitor says no signal, there is no problem in monitor and cable as I checked with 2 monitors and vga and hdmi cable

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crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0