Since it is able to output a display onto external monitor, it seems that the laptop have issues with its component(s). Either it is a Graphics Chipset failure or the LCD Ribbons/Inverter cables are damaged/loose and disconnected from the motherboard. If you wish to repair it yourself, this video shows you the dismantling of Acer Aspire 5315: https://www.youtube.com/watch?v=-ZklRtY7QTE So before ordering any specific replacement components (new LCD screen/video card), I suggest you may want to disassemble the laptop using an online guide and see if all components are properly intact and aligned.
There are many programs implemented with the Gutmann method you've mentioned, especially by overwriting file patterns. If you only want to erase multiple files and not wipe the entire drive, use Eraser. Not sure if you already know this program, but it's essentially a file shredder. It is a freeware and open source security tool to completely remove certain data from HDD. It can overwrite data several times using randomised patterns of binary code. Or, you can use Recuva to find any files that have already been supposedly deleted but still are recoverable, and then securely overwrite them. Be sure to set Recuva to a high number of passes for secure overwriting as well. It'll overwrite the portion of the hard drive where the file lives repeatedly until it "decreases" its chance of recoverability Hope that gives you a bit of ideas
I don't think the fix should be that expensive, $225 cost more than the logic board itself. As you've mentioned, you're able to get the iPhone to be on recovery mode after plugging into computer, so it appears to be some sort of recovery mode loop. You might want to try this software called TinyUmberella, you can use it to exit the phone out of its recovery mode. The program will detect the device straight away after you plug it into your computer, heres the full instructions + download link After its out of the recovery mode, you might need to restore the iPhone, you'll lose current data so here's how to recover those data (Extract data from iPhone through Recovery Mode) Otherwise, if the software doesn't fix it, you might've accidentally pryed/damaged the jumpers off the motherboard/logic board (but I found it quite unlikely that you have digged a "hole" if its still able to turn on, especially since you were only replacing the battery). It seems like a common problem, so you might want to have a look at...
