Screen randomly changes the aspect ratio. Mouse cursor randomly moves,

[MS2233]

An intermittent problem.  Screen randomly changes the aspect ratio.  The mouse cursor randomly moves around the screen going to the top right hand corner.  Then programs close randomly.  Was sent for repairs while under the purchasers warranty (JB Hi-Fi).  Was supposedly fixed but the problem has continued intermittently, though less frequently - but still cannot be depended on, especially when using it to work from home. I have 2 questions:

(1) Any suggestions for what the problem may be before I embark on the unreasonable requirements of the extended care warranty - mailing the computer from Melbourne to Sydney.

(2) There is an alternative option, getting the computer repaired myself and sending the paperwork and receipt to the extended warranty people who say they will reimburse me.  If there is no simple solution, this option sounds best, but not sure how to go about engaging a technician to fix a problem that is intermittent.  Advice/suggestions welcome.

Thank you

[itsmyname]

@MS2233 -- what happens if you connect a USB-mouse, and then disable the touchpad on the keyboard?

Could it be the palms of your hands getting too close to the touchpad?

[MS2233]

Unfortunately, this is an All-in-one, it's a desktop, with a touch screen but no touch pad.   I am using a USB-mouse.  In fact, I have replaced the USB mouse and key board twice because of the problem.  On the third but the problem continues.

[itsmyname]

@MS2233 --  it's a desktop, with a touch screen 

I think that your touch-screen is malfunctioning, causing the mouse-point to "drift" to the top-right corner, and then "clicking" on the "X" at that corner, to close a window.  

Either that, or your computer is compromised, and some remote "hacker" is in control of your computer, causing your mouse-pointer to move, and causing a "click" to close a window.  Disconnect from the Internet (wired & wireless) to see if this will have an effect, since the "hacker" will lose access to your computer.

Can you temporarily disable the "touch-screen" feature of your screen, and use your keyboard & mouse, to see if the symptoms persist?