Other idea is: when was the las maintenance done to your OS (scandisk, defrag, antivirus checking, delete unused files, cleaning recycle bin, etc)?
Hardware maintenance?
Last video drivers, or maybe someone make a change on your system.
Check yout monitor signal cable. Do you have a voltage regulato closer to your monitor/computer?
Hope this help
Mauricio
Be fast like the Fox
Be free like the Penguin
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