As a Former Acer Techie...
As a former Acer techie in the Uk, Acer haven't a problem repairing any hardware defects, since its covered under the limited warranty of the user, however, had the end user decided to read their warranty which came with their trusted notebook, they would have realised that it could be done easily directly.
However, Acer don't guarantee any works carried out by any two bit company, such as PC world, since none of their "Tech Guys" actually know what they are doing.
(I personally applied for a job when desperate, and was turned down for having "Too much knowledge" <In other words, wanting a fresh school leaver, with no actual knowledge about anything relating to PCs whatsoever, other than how to turn it on> so I finally got a job with Acer).
Acer, also don't care what OS your running on your systems, since its your option to do this, hell, if you want to run 3.2 on your system, whos stopping you?! You bought it, you use it, not Acer!
So, PC world, another one against you...
However, the only thing against this, is if the fault is deemed Software related, then Acer will ask you to reimage the hdd with either the disks provided, burnt off on original boot up, or using the "One Button Recovery Mode", if the engineers see you have failed to do this, then they will recover your system firstly, and if this still doesn't work, then they'll continue replacing hardware (so again, back up your shitz before sending).
Also, PC world should completely stop offering services / repairs and upgrades, since all you'll get is a formatted system handed back to you, with very little explaination.
I once asked PC world for Printer Memory, and all they could continuously show me, was PC Ram, or Printer Ink. Of course I was only winding them up, and ended up buying a nice set of 2.1 speakers from them at £15, but still! They shouldn't hire retards.