I took my MacBook in for repair last week, and have just booted into Vista, will I have to reactivate? If you aren't sure how do I check the activation status
open 'computer' and click on one of the tabs at the top..can't recall off hand which one but it will bring you to a screen with the experience index score and stuff and tells you wether it is activated or not at the bottom of that window
Easiest way is to right click My Computer and select Properties. That will show basic information about your computer and at the bottom you will see a section called Windows Activation. That's where it will say if it is activated.