My C27 Freezes. needs to turn off. won't load up properly and has lines

What is the exact C27 AIO model number, is it the C27-1655 or the C27-1700 AIO? As its a bit hard to advise you precisely on any fault(s) if we don't know the exact model number C27 that you have, as there are many.

Anyway, I will presume that your AIO is the latest or the fairly new model number C27-1655 or the C27-1700 and if its only 8 months old then you should NOT open it up, as you will void your Acer warranty! I know how hard it is when this PC is your working tool, but your AIO might have a faulty GPU or you have done something wrong in updating the GPU driver and especially a bios update, which needs your AIO to be sent to Acer Support so that the Acer techs can look and analyze the GPU problem that you have or screen problem that you might have, or even the motherboard might need changing, these are all probabilities of what could be wrong with your C27 AIO?

The C27 that I've looked at which is the C27-1655 and the C27-1700 don't have a GPU firmware update, they only have a bios update, where did you get the firmware update from? Anyway, lets just try the basics fixes, so try and do the following, as the problem could be a driver or the actual screen connection and its circuitries that could be faulty, which you need to send this AIO to Acer to fix, so be aware of that first.

If its a GPU driver or software of this AIOs either GeForce MX330 or the GeForce MX550 type NVidia GPU. first install a software called DDU uninstaller and follow this softwares guide of how to completely uninstall all the GPU drivers on your AIO PC. Then download the appropriate GPU drivers for either of these two separate model GPUs, which is the same for both, and its the NVidia newest Win-11 driver the Version: 531.79 WHQL driver. Try that as I don't know which firmware driver you have updated to but doing firmware updates is very dangerous especially those that come up in Microsoft Win-11 Windows Updates, as those Window Updates bios or GPU firmware updates brick PCs and should not be installed or updated with! Give us more info and good luck in fixing this problem.

Let us know how things turn out with Acer support. My guess is they'll go through that first level diagnostics it sounds like you were in, followed by a trip to a service center for actual repair.