Since you are using the internet from another computer, presumably safe, do a google search for the EXACT error message, in quotes, ie "Hard drive configuration is not set to the factory fefault" ... add Acer too if it helps narrow the # of hits, outside the quotes of course
With error messages, chances are someone else has had that problem.
If you can find a fix, terrific. It's a very unusual problem - maybe someone here can help. If you go to a help service it's going to cost you $$$ -- do this only if have large amounts of data to be saved, or you do not have the master install disks.
Worst case, at least you have access to the computer .. backup your important stuff and set those disks aside, you'll have to scan them later. Boot from the install disks (may have to go into CMOS and set CD/DVD ROM as the boot drive priority). Reformat the drive, Reload the OS.
Make sure you spend the money for a good firewall / antivirus software package so you're not in this boat again. Don't insert the backup disks/CD's on an unprotected machine, or you'll be back where you were.
This is just based off what you said. I don't know your background. It could be simply that you need to reset your modem / router to get your internet back.
It could be that the internet issue and backup restore are 2 unrelated problems. .. like oh so, can't connect to the internet because the router key isn't up to date or you accidentally set your neighbors wireless as the default (or you were using theirs and they changed / added the key) .. and you can't do the restore because you were cleaning up the HD one day and killed the backup files.
I've known people that accidentally set their internet to the wrong router (neighbors), simply because it wasn't encrypted and it worked. They still paid for their own unused internet service though, go figure. Apparently, it happens.