I've got problem with Mikrotik 5009. Device is not booting, I've tried to reset, but no success. Port 1 blinking, but I can't reach device from PC. From PC I can see messages - "Cable connected" and "Cable disconnected"... Can someone suggest something?

Have you tried netinstall?
https://help.mikrotik.com/docs/display/ROS/Netinstall

Its not booting or it does a boot loop ?

From OP description, probably boot loop...

Thats what i think too...

Yep, I've tried Netinstall, I can't see Device after resetting, I've tried several times... In Windows I can see that Network Adapter shows - "Unidentified Network" and "Cable is disconnected"

Yep, I've tried Netinstall, I can't see Device after resetting

Did you actually netinstall the device ?
And after that the problem persists ?

Yep, I've tried Netinstall, I can't see Device after resetting, I've tried several times... In Windows I can see that Network Adapter shows - "Unidentified Network" and "Cable is disconnected"

I recommend watching my video on YouTube about how Netinstall works so that you're doing it all correctly.
https://www.youtube.com/watch?v=-mOGD1-Uv2Y