If this was the full (paid) version you should have received the product key.  It sounds like it was just the "trial" version and in that case you would have to buy it from Microsoft to get the product key.   If it is the full version you will have to call Dell to get the key.
Hi, I recently bought a XPS 17 with preinstalled Microsoft 2010 Student , when I start Office it gives 3 options -activate , -purchase , -trial, when I click activate it asks for a 25 number activation key, The only key I can find (wich is also the only key ON my laptop) doesn't work, as it is the Windows 7 key and not the Office key. In the package there was no other key or disc except some manuals for my laptop. How can I activate my Office? I urgently need it for school and would like to have Office activated.  Thanks in advance,  A.C
Microsoft Office 2010 activation.