Altera Monitor No Longer Connects After Restart

I'm using Altera Monitor 15.0 with a Terasic DE2-115 development board on Windows 10.

Altera Monitor will no longer connect to my board. I can download a system onto the board but compiling and uploading a program fails. I'm using the stock DE2_Basic_Computer without any changes. I've tried programming in Altera Monitor and through Quartus by uploading the NiosII files to the EPCS64. I have tried this process with both basic computer and media computer - both using the stock files.

This system setup as described above was initially working fine. After closing Altera Monitor and returning to work later, I have the problem described above. Below is a copy of the Altera Monitor Info & Errors window from the point of system download to error after compilation attempt. I also noted an error saying that the system couldn't run because of little-endian/big-endian conflict. I was unable to recreate this message for this post.

NOTE (1): I believe I had the same problem the other day. Thinking that a system file got corrupt, I purged all Altera software from my computer and reinstalled, which fixed the problem. But there has to be a better solution than re-installation.

NOTE (2): The C program I'm trying to run is also below

UPDATE: I've since tried using Altera Monitor in a brand new Windows 7 installation on the same machine (I dual booted to a second hard drive) to no avail. Furthermore, I can upload custom VHDL compilations in Quartus to the EPCS module and everything works correctly. I can also install a NiosII processor on a DE0-Nano and that working in Altera Monitor. I'm also unable to connect to the DE2-115 through the Nios II EDS - I get the same error.

C:/altera/15.0/quartus/bin64/quartus_pgm -c "USB-Blaster [USB-0]" --auto

1) USB-Blaster [USB-0]

020F70DD EP3C120/EP4CE115

Info: *******************************************************************

Info: Running Quartus II 64-Bit Programmer

Info: Version 15.0.0 Build 145 04/22/2015 SJ Web Edition

Info: Copyright (C) 1991-2015 Altera Corporation. All rights reserved.

Info: Your use of Altera Corporation's design tools, logic functions

Info: and other software and tools, and its AMPP partner logic

Info: functions, and any output files from any of the foregoing

Info: (including device programming or simulation files), and any

Info: associated documentation or information are expressly subject

Info: to the terms and conditions of the Altera Program License

Info: Subscription Agreement, the Altera Quartus II License Agreement,

Info: the Altera MegaCore Function License Agreement, or other

Info: applicable license agreement, including, without limitation,

Info: that your use is for the sole purpose of programming logic

Info: devices manufactured by Altera and sold by Altera or its

Info: authorized distributors. Please refer to the applicable

Info: agreement for further details.

Info: Processing started: Sat Oct 31 13:53:12 2015

Info: Command: quartus_pgm -c "USB-Blaster [USB-0]" -m jtag -o P;C:/altera/15.0/University_Program/Computer_Systems/DE2-115/DE2-115_Basic_Computer/verilog/DE2_115_Basic_Computer.sof@1

Info (213045): Using programming cable "USB-Blaster [USB-0]"

Info (213011): Using programming file C:/altera/15.0/University_Program/Computer_Systems/DE2-115/DE2-115_Basic_Computer/verilog/DE2_115_Basic_Computer.sof with checksum 0x00C6516D for device EP4CE115F29@1

Info (209060): Started Programmer operation at Sat Oct 31 13:53:14 2015

Info (209016): Configuring device index 1

Info (209017): Device 1 contains JTAG ID code 0x020F70DD

Info (209007): Configuration succeeded -- 1 device(s) configured

Info (209011): Successfully performed operation(s)

Info (209061): Ended Programmer operation at Sat Oct 31 13:53:21 2015

Info: Quartus II 64-Bit Programmer was successful. 0 errors, 0 warnings

Info: Peak virtual memory: 266 megabytes

Info: Processing ended: Sat Oct 31 13:53:21 2015

Info: Elapsed time: 00:00:09

Info: Total CPU time (on all processors): 00:00:01

nios2-elf-gcc -g -O1 -ffunction-sections -fverbose-asm -fno-inline -mno-cache-volatile -mno-hw-mul -mno-hw-div -I"C:/altera/15.0/nios2eds/components/altera_nios2/HAL/inc" -DSYSTEM_BUS_WIDTH=32 -DALT_SINGLE_THREADED -D_JTAG_UART_BASE=268439552u -Wl,--defsym -Wl,nasys_stack_top=0x8000000 -Wl,--defsym -Wl,nasys_program_mem=0x0 -Wl,--defsym -Wl,nasys_data_mem=0x0 -Wl,--section-start -Wl,.exceptions=0x20 -Wl,--section-start -Wl,.reset=0x0 -Wl,--script="C:/altera/15.0/University_Program/Monitor_Program/build/nios_cpp_build.ld" -o "D:/Keith/Documents/Module4.elf" "D:/Keith/Documents/School/ODU/ECE484W/Module4.cpp" "C:/altera/15.0/University_Program/Monitor_Program/lib/jtag_uart.c"

ELF generated at D:/Keith/Documents/Module4.elf.

nios2-elf-objcopy -O srec "D:/Keith/Documents/Module4.elf" "D:/Keith/Documents/Module4.srec"

SREC generated at D:/Keith/Documents/Module4.srec.

Using cable "USB-Blaster [USB-0]", device 1, instance 0x00

Resetting and pausing target processor: FAILED

Leaving target processor paused

# define COUNT 1000
# define SERIAL_PORT 0x10001010
# define SEVEN_SEGMENT_PORT 0x10000020
/*
// Gets an integer from the serial data register and returns an int result
*/
int getInt(){
    volatile int * serial_ptr    = (int *) SERIAL_PORT;
    volatile int serialData    = 0;
    volatile int data            = 0;
    volatile int counter         = COUNT;
    
    bool found = false;
    
    while(!found){    // Block until Serial Data Available
        serialData = *(serial_ptr);    // Get Byte 3
        if (serialData & 0x00008000){ // Check for new data
            found = true;
        }
        
        // Delay counter
        counter = COUNT;
        while(counter>0){counter--;}
    }
    
    data = serialData & 0xFF;    // Store Byte 3
    data = data << 8;
    serialData = *(serial_ptr);    // Get Byte 2
    data += serialData & 0xFF;    // Store Byte 2
    data = data << 8;
    serialData = *(serial_ptr); // Get Byte 1
    data += serialData & 0xFF;    // Store Byte 1
    data = data << 8;
    serialData = *(serial_ptr);    // Get Byte 0
    data += serialData & 0xFF;    // Store Byte 0
    
    return data;
    
}
/*
// Converts an integer into a 4 section 7-segment display. Capable of values -999 to 999
*/
int intTo7Seg(volatile int &input){
    // Active high 7-segment display LUT
    volatile char digits  = {0b0111111, 0b0000110, 0b1011011, 0b1001111, 0b1100110, 0b1101101, 0b1111101, 0b0000111, 0b1111111, 0b1100111, 0b1000000};
    volatile char hundreds = 0;
    volatile char tens = 0;
    volatile int output = 0;
    
    // Checks for negative value
    if (input & 0x80000000){
        // Two's Complement Input
        input = ~input;
        input++;
        // Store "-" in Left most segment
        output += digits;
        output = output << 8;
    }
    
    // Separate "Hundreds" place from integer value
    hundreds = input / 100;
    input     = input % 100;
    
    // Separate "Tens" place from integer value
    tens     = input / 10;
    input     = input % 10;
    // Store 7-Segment values by integer into output
    output += digits;
    output = output << 8;
    output += digits;
    output = output << 8;
    output += digits;
    return output;
}
/*
// Program main
*/
int main(){
    volatile int * seven_seg_LED     = (int *) SEVEN_SEGMENT_PORT;
    volatile int brightness = 0;
    
    while(1){
        // Get Brightness Value from Serial
        brightness = getInt();
        
        // Update 7-Segment Display
        *(seven_seg_LED) = intTo7Seg(brightness);
    }
}