Checked box only thing inside is a voucher code for my purchase. Once I register it asks for serial number not voucher code. Troubleshoot says it will be send to email but only email sent prompts me to register which is already done.

@SirWilson-Brown A voucher code (don't post it here!)? I would guess you now need to open the online store on Magix.com and buy Music Maker while entering your voucher code which would reduce the price to zero.

ok it's saying enter serial/coupon code to redeem credit so im guessing this it what im looking for before i enter the information.

@SirWilson-Brown Here I found a menu entry where you can enter coupon codes. Maybe try this:
Help > Music Maker Store > Redeem credit...

Yes that's what I was just on an it's saying my code is invalid. I brought the program from the store thinking they still had them on CD ROM upload.

How did you get your serial number, did you purchase online or in store? if you don't mind my asking.

@SirWilson-Brown Have you tried visiting Magix.com and putting Music Maker into your virtual basket and entering the coupon code via checkout? I bought my version on Magix.com

There are sometimes problems with the codes from Best Buy. It happens that Best Buy doesn't inform Magix that you bought Music Maker. Until this happens the coupon is not activated because Magix doesn't know that you bought the software. Normally this information is sent automatically after purchase but sometimes Best Buy isn't sending it out. So, it could be that you are one of those customers that got unlucky. If this is the case you need to contact Best Buy to solve this problem for you.