The service tags not recognised, what model of Dell is it?

Do you have a Dell Windows 7 Professional Reinstallation DVD?

If the tag was on the bottom its not a model from 2009 Windows 7.

Systems with windows 7 from 2009 have the Tag in the battery bay where it wont get rubbed off.

The forum is not a source of free windows keys.

If you cant read it you have to buy a new copy of windows.

5 May 1999     Windows 98 SE
17 February 2000     Windows 2000
25 October 2001     Windows XP     
31 October 2002     Windows XP Media Center Edition
30 September 2003    Windows XP Media Center Edition 2004
12 October 2004     Windows XP Media Center Edition 2005
25 April 2005     Windows XP Professional x64
8 November 2006     Windows Vista  Business
30 January 2007     Windows Vista  Home
22 October 2009     Windows 7     
26 October 2012     Windows 8     
18 October 2013     Windows 8.1     
29 July 2015     Windows 10    

The service tag is recognised on Dell's support web site and I would like to know if there is a way to get the original Windows 7 professional key that was supplied with this laptop and service tag. I am not looking to get a 'free' key as one person responding put it and it is not my fault if the key is supplied in such a way that it gets worn by day-to-day use of an end user and before I personally joined the company.

Yes I have a copy of Windows 7 Professional installation CD.

Any help is appreciated.