I generally can help with AC backup.
Dell wouldn't not do it to save money. They are very, very good. Usually, if under warranty and you call at 5 pm, it will be at your office at 10 am. Also, look and see if you have like a 5/24 onsite support, and then just call and say, I want a tech at my office tomorrow. Basically, they have to.
On the other hand, if they didn't cooperate which they will, just go to Best Buy and pick it up. Or pay Dell. You can argue with them later. However, when it is mission critical, if you have the onsite protection, tell them you want someone out.
