Problem Loading New Programs

I’m very new to this whole skill set. I’m currently taking a class on using micro-controllers and today in class I was experimenting with the Loop sketch and I was messing around with the formulas. At first I changed the “For i=0 then…” formula before the Loop and changed it to “a=1…” and so on. Then I plugged it into the Loop sequence and changed i’s to a’s then I uploaded the program. It loaded and the sequence went through LEDs in the bread board once and stopped. All the wiring was right so I can’t imagine I fried the board,but the program is still on the board and its on the fritz. Does anyone know how I can delete the program/sketch off my new Arduino or how I can reset it to allow for a new program to be put on it. I might have pulled the Arduino out of the USB cable jack when I was trying to upload a new program after I saw this one glitch up, only because the computer and the program seemed to have froze up.

usually you just upload another program, it will overwrite the existing one in Arduinos processor.

Make sure you have the correct serial port and board type selected in the Tools menu in the Arduino software.

Another good check is to watc the board during the upload, there are two tiny little surfacemount LED’s on the board that should blink a bit during the opload, the are connected to the boards serial RX and TX lines, and blink everytime serial communication takes place.