Dell India — Not providing the product key of operating system.

Address:	Kolkata, West Bengal, 604307
Website:	www.dell.co.in

I had purchased dell insiron n5010 on december, 2010. The system has preinstalled softwares (Windows 7 home basic, ms office 2007). Last week i tried for reinstallation as my hdd was damaged. When i entered the product key while reinstalling windows, i got the message that the product key is not valid. When i contacted the microsoft, they clearly told that they are not responsible for the softwares provided by dell, as it is oem and pre-installed software. When i contacted dell india, they are refusing to answer or resolve the problem. I know my system is out of warranty. Here i am not asking the service, i am asking about the product key provided by them which is invalid. But dell india is directing me to contact microsoft. Kindly do the needful.
Thanking you.
Yours faithfully,
J.K. Aravind