Salamat po sa replies and suggestions niyo. Eto po so far mga ginawa ko:
check video/resolution settings from options in CF: no go
change CF from full screen to windowed then back to full screen: no go
check resolution settings (display) in Control Panel: no go
check monitor settings (manual): no go
reset monitor settings: no go
replace/copy CF folder from working PC: no go
delete CF folder (documents): no go
replace/copy CF folder (documents) from working PC: no go
disconnect/reconnect cables from tower to monitor: no go
check refresh rate (isang option lang available 60Hz pero sinelect ko pa rin at "apply": no go
replace monitor: YES!!!!!
So far po working na siya. Ginamit ko monitor ng server. Yung monitor nga po talaga may problem at hindi file/program ng CF. Pero I would NOT consider this resolved kasi hindi ko pa po alam ano specifically nagtrigger ng issue na 'to (dahil nangyari siya right after update at sa isang PC lang). More than making the PC work, mas gusto ko sanang maintindihan anong nangyari, bakit nangyari at anong pwedeng gawin (without replacing the monitor since okay naman siya sa ibang games/applications). Pero nagpapasalamat po talaga ako sa lahat ng suggestions niyo. I'll keep them in mind para kung may ibang issue in the future, pwede ko silang gawin ulit. SALAMAT PO!!!