(redirected) Windows Update Disabled

I had bought a Dell Laptop with Windows 7 OS pre-installed. I do not know how but then, since a month ago, when Microsoft stopped the support for Win XP, I think there was some problem (some Adobe download problem) & suddenly the Windows Update of my Windows 7 OS was permanently disables. During these times I ran from pillar to post to sort out the issue, but all in vain. When I contacted the Microsoft Customer Care, they asked me to contact the OEM to sort out the issue. And when contacted the Dell Customer Care I was told to pay out Rs. 1374 to reload the OS. Sir/Madam, I am on a touring job & why should I pay out more, for which I had already paid for. And more of a shocker !! When I again tried to contact Microsoft via chat today on 20/May/2014, I was told that my version of Windows 7 OS is not a genuine one. Wow! The self help @ Microsoft portal is too not detecting the issue properly. For this reason my antivirus is too not working. Everytime I might not be able to carry the OEM OS CD. I am too a displeased with the kind of support you provide. Please help me out to resolve the issue.
SITAKANTA