Vista Ultimate Activation Backup?

I Am Using Windows Vista Ultimate In my Laptop Rite Now. I want to format it but have lost the Windows Key since i Installed it many months ago. Any way to Retrive it or make backup of Activation? It was Upgraded by Hp Service Center on Payment in uk. When i Contacted them they said since i have lost the key i need to purchase another..

you should contact microsoft. they'll have a way to verify it and give u a replacement key.