I am using a HP Pavilion 15 (J2C46PA#ACJ) with Windows 8.1 for about a month now. Since a week I have noticed that the computer lags in general(slow response to double click, .exe files take more than normal time to open) and specially when multitasking. For example if I am playing a video in VLC and open Chrome in between the video stops for brief moments and also produces a screeching sound (something like the sound in "blue screen error"). At the same time Chrome lags too and gets slow.Even if the video gets normal after Chrome has opened, on opening a new tab the same thing repeats with the scarry screeching sound.