the one I have is exactly as you describe too.
When it is having its episode the mouse pad is totally random and you cannot select anything although the touch screen i less so but I cannot select my password via picture in win 8.1.
Again i have scanned for malware and virus, the machine has all the latest from microsoft and HP.
My ralink wireless card is next to useless if i am more than 2 meters from the router is this a common fault also?