I have been having sporadic crashes for 2 weeks now; mouse simply disappears from screen while surfing the net and everything locks up; BUT, the restart causes the big problem: I get the pink screen while the apple logo is displayed, but then when the screen turns gray, no mouse icon appears and everything freezes. The Apple Hardware Test shows this fault: 4SNS/1/40000000: VD0R-18.711 But I can't find out anywhere what failure that signifies. HELP please!
Pink screen is typically VRAM / GPU and much less often a cable or screen issue. If you can’t afford a flat rate repair ($300 in the US typically) that will fix everything wrong with your portable - you’ll want to do an erase install to be 100% sure it’s hardware and not software.
Get a backup of course since with hangs and crashes - Time Machine with hourly backups will save a large amount (as well as covering recent changes) of data loss when this instability eventually makes the system unbootable or you lose the file system.
Also, don’t overlook that with crashes and hangs and various hardware symptoms, you may have several issues going on making it hard to know which one to attack first. This means getting it to Apple or an authorized technician with better tests than AHT a good use of your time.