Refurbished unit or not, consumer law applies, and Currys must rectify the fault. They may have told you to contact Acer, but you didn't have to do that. You've done it now, and Acer appeared to have washed their hands of the computer, so you must go back to Currys and tell them you want them to fulfil their obligation to you under the terms of current legislation.
You say the machine came with a full years warranty, and as Acer have said they can't help I assume the warranty wasn't from them - it must have been from Currys.
Currys suggestion that you contact Microsoft is ludicrous, unless the problem is with Vista, and not with the machine itself.