A block of fine black lines has appeared around my mouse pointer.
My mouse pointer has suddenly grown a block of fine black lines about 5/8" deep x 3/8"wide. It has also stopped working. It moves around the screen, but won't activate anything I click on. Re-seated the memory chips, zapped PRAM NVRAM & SMC, did a complete re-install after zero-ing out the hard drive. Still happens.