I have an Acer Aspire 5740 same spec as yours above and I have discovered a similar fault. Have you been able to fix your laptop, if so any ideas how I could do the same?
Had the same problem with my laptop. Opened it up and the power jack was broken. I bought a replacement and soldered it on myself. The replacement power jack is part number PJ014. It has a 1.64 mm center pin.
I know this is a really old thread but it was highlighted in the resources.
Three months old? WARRANTY! A bit late now though...
Jan/Feb 2011 there was a problem with the new Intel Sandybridge chip which stopped recognising SATA connections.
I do trust you got your problems sorted.