Hi Sorry to hear of the problem with your laptop computer.
The first thing that needs adressing is the overheating problem….each time your computer overheats and the heat sensors shut it down you are risking damage to the CPU and other sensitive areas…. it will only take so much of this before a potentially catastrophic failure is likely to occur….so apart from repair purposes you should not use the computer at all until temperatures can be controlled.
These particular machines were particularly prone to overheating and the fix is not simple or straightforward in a lot of situations.
Its important with any laptop computer that the cooling fans and passages are kept free of a build up of dust and airborne detritus, and if by any chance the computer has been operated on a soft surface, for example a couch or settee, or a bed, of a towel or any item of clothing then this makes the cleaning even more important.,and in these circumstances a dismantle and internal clean will be a good idea.
Providing the computer has been used on a hard surface, a table for example, then it may be possoble to perform a partial clean by the judicious use of a cylinder of low pressure compressed air (an air duster available from most computer shops for a pound or two or a dollar or three)
The use of a heat pad, or chiller pad (fan operated) under the computer helps to draw away the heat and may be sufficient to avoid the expense of a major stripdown, possible fan replacement with the usual fairly high labour charges that have to be charged for this sort of work.
If you can keep the room temperature down (ambient temperature) to say 15 to 17 degrees C this will also help, as will, directing a deskfan on to computer to help move the heated air.
There is rarely very much space underneath a laptop computer…only a few millimetres between it and the table or desk….so elevating it by say 25 millmetres or so ) using 4 india rubbers (erasures) one in each corner may help considerably..( make sire you do not cover any vents, grills or fans with them or you'll make matters worse!
A lot of folks fail to appreciate that a laptop needs at least 75 millimetres as a clearance around all its sides…anything that gets closer than this can lead to an overheat problem.
So the first job is to get the temperatures down to a reasonable level, by operating on a hard surface elevating it, using a fan assisted chiller pad underneath after having completed a throrough external clean using an approved air duster or an strip down and internal clean with or without fan replacement if necessary.
Here's a link that you might find useful:
http://www.laptopsarena.com/hp-laptop-pavi…v4-overheating/
some of the responses from owners of your model are quite interesting!
Then it would be sensible to visit the malware removal forum and post one of the logs requested in this topic, so that the experts over there can see if malware is present on your computer
http://forums.whatthetech.com/index.php?showtopic=106388
Good luck
Regards
paws