Arduino Mega abruptly refusing to communicate with any port or pc

So the issue revolves around the arduino being unable to connect to any port on any computer. an intersting quirk is that when the power shield is unpowered, it will show up in the port listings, however when the power shield is plugged into the wall, the arduino itself then does not show up on the port listings. The only inputs and outputs are the six servo ports (labeled 8-13). This issue was shared with a few other groups working on a similar project. This issue did not appear for the first few weeks of testing, using the same code and outgoing connections. any help would be appreciated.

Below is the error code received when trying to re-upload the code to the arduino mega, after utilizing the trick stated above to get it to list itself in the port listings.

Arduino: 1.8.9 (Windows 10), Board: "Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)"

Sketch uses 7974 bytes (3%) of program storage space. Maximum is 253952 bytes.
Global variables use 626 bytes (7%) of dynamic memory, leaving 7566 bytes for local variables. Maximum is 8192 bytes.
avrdude: ser_open(): can't set com-state for "\.\COM12"
avrdude: ser_drain(): read error: The handle is invalid.

avrdude: ser_send(): write error: sorry no info avail
avrdude: stk500_send(): failed to send command to serial port
avrdude: ser_recv(): read error: The handle is invalid.

avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: ser_send(): write error: sorry no info avail
avrdude: stk500_send(): failed to send command to serial port
avrdude: ser_recv(): read error: The handle is invalid.

avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: ser_send(): write error: sorry no info avail
avrdude: stk500_send(): failed to send command to serial port
avrdude: ser_recv(): read error: The handle is invalid.

avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: ser_send(): write error: sorry no info avail
avrdude: stk500_send(): failed to send command to serial port
avrdude: ser_recv(): read error: The handle is invalid.

avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: ser_send(): write error: sorry no info avail
avrdude: stk500_send(): failed to send command to serial port
avrdude: ser_recv(): read error: The handle is invalid.

avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: ser_send(): write error: sorry no info avail
avrdude: stk500_send(): failed to send command to serial port
avrdude: ser_recv(): read error: The handle is invalid.

avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer
the selected serial port avrdude: stk500v2_getsync(): timeout communicating with programmer
does not exist or your board is not connected

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

A "power shield" ?

Think you might want to read the posts at the top of the forum and add more detail about the mysterious shield.
It does sound like it may use two of the pins that need to be available to the USB port.

Best guess without more details.

Bob.