I have an Acer Extensa 7220 laptop which is now nearly 4 years old. I have twice experienced the problem of cracks appearing on the cover close to the left hinge. When my laptop was only 9 months old a crack suddenly appeared at the left hinge. Fortunately it was still under guarantee and Acer replaced the cover free. Yesterday I noticed that a small hairline crack has now appeared close to the left hinge. I have always been extremely careful with my laptop and have always stored it in a case when not in use. I've never once left it sitting around. I would never buy an Acer laptop again as I think it is highly overrated as a brand name! Apart from the problem with cracks my hard drive has also crashed twice. I was led to believe that Acer was the leading make on the market. but sadly from my persnal experience this has not been the case.
