so why does it only start spinning once it runs into something?

my battery pack broke, and now I am powering the robot by plugging it into a computer. since I have done this, the motors no longer spin with full power. I tried to use the exact code given in Workbench part 3f, and it doesn't move. I also had problems since once it "runs into" something, it just starts spinning in circles, even when there is nothing in front of it. why is this, and how can it be fixed?

this code doesn't work:

void setup() {
  // put your setup code here, to run once:
#include <SmartInventor.h>//include library
}

void loop() {
  // put your main code here, to run repeatedly:
SmartInventor.Buzz(200,8);//make some noise-pitch,200,tempo,8
delay(500);//whait 1/2 a sec
SmartInventor.Buzz(500,8);//make some noise-pitch,500,tempo 8
delay(500);//wait 1/2 a sec
}

when i try to verify it, i get this error message:

Arduino: 1.8.5 (Windows 10), Board: "Rokit-SmartInventor-mega32_v2"

C:\Users\Efraim\Documents\Arduino\libraries\program_the_buzzer\program_the_buzzer.ino: In function 'void loop()':

program_the_buzzer:8: error: 'SmartInventor' was not declared in this scope

 SmartInventor.Buzz(200,8);//make some noise-pitch,200,tempo,8

 ^

exit status 1
'SmartInventor' was not declared in this scope

This report would have more information with
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I'm getting this error message when I try to verify the default programs:
Arduino: 1.8.5 (Windows 10), Board: "Rokit-SmartInventor-mega32_v2"

C:\Users\Efraim\Downloads\rokitarduinov1-0-9-1\rokitarduinov1-0-9\Rokit\Smart\Recovery_Smart-Inventor_160322\Recovery_Smart-Inventor_160322.ino:64:27: fatal error: SmartInventor.h: No such file or directory

#include <SmartInventor.h>

                       ^

compilation terminated.

exit status 1
Error compiling for board Rokit-SmartInventor-mega32_v2.

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