HP Pavillion 15 is unresponsive. Starts up fast on to the log on screen, then the desktop takes ages to load, sometimes not all the apps on the taskbar will load. If I try and open anything, sometimes it will load, if it does, it will not respond then the screen goes black and loads the desktop slowly again. I've tried opening task manager, if it does open it shows no apps running or anything. I don't know what the problem is.