Does the Service Tag end with something like -595 or other number ending in 5?
What is the source of the computer? Was it purchased as a Refurbished unit, or from a non-Dell source? If purchased new, this is a warranty issue.
Have you really talked to Tech Support on the phone? You can alwasys change Telephone Service Techs. If the person you reach is not helpful or hangs up on you (which happens to me all the time), call back, then ask to be transferredd to a United States tech support person because the tech support is rude or unhelpful. Be ready to recprd the call if you can, then ask for permission to record the call (otherwise it is illegal to record their voice), then stay on the line.
Their system will detect that you have repeatedly called back.
We find the best support outside the US comes from the techs in the Philippines, Jamaica, and Panama.
You might also call at a time that is 9 a.m. in India.
Keep trying. It will pay off. You may then learn what is possible. Sometimes you will have to pay for the BIOS change, if a previous owner has tried to bypass the BIOS password... but Dell will tell you what is possible.
Also, online searches will bring you in contact with people who perform such service on Dells. AGain, it is never inexpensive. Same with Sony
Buy a Thinkpad, Gateway, or HP next time... or just buy a new one.