it has been a week since i didn't restart my PC so i thought it would be a good idea to restart it while i was on windows. but when it restarts nothing happens. it shows mainboard screen then screen goes black where it normally would show 'choose your operating system' screen.

luckly i had ubuntu on my pendrive, it started without any problem. i can open files on my hdd, i think there is no hardware problem, everything seems working good.

i didn't make any critical change while i was on windows as far as i remember other then installing and uninstalling softwares. i haven't been using ubuntu for a while so there shouldn't be problem caused by ubuntu.

does the situation look familiar to you? What's the problem, any idea, suggestion?