How much is a 1 year old windows 7 acer laptop worth excellent condition

Considering we have no idea what the technical specs are or what model it is we can't help you there.

Hi  

As a general rule....second hand cuts 50% off the new price (trade) and any damage or scratches etc another 10 to 20% ....

All the best Brett  

I would say, 50 to 60 percent of as-new price. It of course depends how new the model was when you biught it.