I also have Acer Aspire One, thought 772, and I also have just bought it (over Christmas)
Today I got this message "Check cable connection pxe- m0f exiting intel pxe rom no bootable device insert boot disk and press any key"
I tried to follow your instructions above but I cant even get into Bios.
Also, this is a small notebook with no CD/DVD drive, and no copy of the operating system was provided .
Any chance to solve it without giving it back for guaranty repair? (bit painful for me, I live in different country then the country of purchase)