Really, it's just a matter of how a program looks at the expression. If you have a negative sign (not a minus sign), then it automatically treats it as (-2). If you use a minus sign, then it treats it as -2. When you square it, you have -(2^2) with a minus sign and (-2)^2 for the negative sign. Both are correct like DaveC said. This is why you should use ()'s with anything ambiguous. For mIRC, use ()'s and it will work just fine.
