How do I check the warranty? Do I need to take the warranty card or something? The box didn't have any warranty card. The dealer said that it's 5 year onsite warranty.

Further updates on DVI cable issue:

Skope Computers has refused to help in this case. I have called them multiple times and everytime I hear them say that the lot which they have received doesn't have DVI cable. I really should have bought it from SMC but only bought it from them as there were the authorized retailer.

I had been trying to reach Dell for last couple of days but wasn't able to. Finally emailed them and got the reply saying that they can't help in this case as the order was not directly placed by me but the retailer and the retailer hasn't contacted them for this issue.

I managed to get hold of one person at Dell Customer Care today after waiting for over 30 minutes on the line and he has said that they will check the order quotation and see the details. I hope they will be able to do something.