On the original (now dead) HDD, there was a factory reset partition.
There was also a function to create your own DVD for the factory reset, in the event the actual hard drive died. As seems to be the case here. When the laptop was brand new, it prompted you to create that DVD. Sadly, almost no one does this.
So, you don't have the drive, OR the factory reset DVD.
Is the sticker with the license key still on the bottom and readable?
If not, contact Acer. They will probably send you that DVD. But it will probably cost a few $$$.