Acer Aspire 4520 is a wonderful yet economical laptop from Acer. You can get it for as low as $700. I bought this few months back and I am quite happy with it. It has every thing you would expect from a laptop today. The hardware configuration of my laptop is as follows (Hardware specifications may change according to the country):
The Problem: Though this is a wonderful laptop, I faced few problems with it. For example Linux drivers for all the components are not included even in the biggest distros. Though with some geeky tactics I managed to get it to work successfully. The other problem that most of the Acer 4520 user face is keyboard Lag problem (also known as Sticky Keys problem) where sometimes the key respond some time after it has been pressed or even few key strokes may not get registered if you type too fast.
The Solution: After spending some time in searching the net for the solution of this problem I finally got a working solution. The latest Bios update for this laptop eliminates this weird problem. You may download the Bios update for Acer 4520 from:
I hope this will solve the problem with your system too.
UPDATE: You can download the latest firmware and drivers for your Acer Aspire 4520 from Acer Official Website: http://support.acer-euro.com/drivers/notebook/as_4520.html