We have an Acer Aspire V3-771-6846 that, after being disassembled, having the CMOS battery reseated, and reassembled works great for a period of time. In our shop, it will boot properly and run just fine with no errors. We are giving it back to the customer, who is getting it to generally work about once at home, and then they bring it back with it only displaying the Acer logo (no F2 or F12 options showing up) and then going to a black screen with a solid cursor line at the top left. At this point, there is no further response from the computer, although it will turn the screen on and off if we press the Fn+F5 keys and the wireless will turn on and off with Fn+F3.
When it is like this, the Acer logo will sometimes stick around for a couple of seconds before switching to the black screen, and then at other times gets locked into a patter where it only flashes on screen for a split second before going black. Occasionally, it gets stuck in a loop where it goes to logo, black screen, then restart and repeat indefinitely until we press the power button.
Any ideas? Seems like a motherboard issue but could also be that something connected to it is shorting out, preventing it from posting properly.