Couple of issues with my pc

Hi guys,I'm experiencing some weird issues with my desktop. 1.it opens up very slow (Windows 10) 2.sometimes it freezes with loud buzzing sound and needs to be resetted 3.when watching films,same thing happens,freezes for few secs 4.same thing happens when playing games. Got no idea what that could be,i've reinstalled windows,cleaned up everything inside,checked if it's overheating-it's not.Might it be ram problem,possible one of the sticks failure?...I would appreciate any suggestions.Thank you.