I need to press a key on my keyboard to start factory recovery

Hi and welcome to Fixya!

In order to revert the machine back to its factory setting, you need to have the recovery disk (if you don't have it, call the warranty support line of e-machines so they can provide it to you).

To restore Windows from your recovery discs, you will need to
insert the first backup disc and enable the F12 Boot Menu via the BIOS Setup
Utility.
1 Turn on your computer and insert the first system recovery disc into the
optical disc drive. Restart your computer.
2 During startup when the eMachines logo shows, press the F2 key to enter
BIOS Setup, where you can set system parameters.
3 Use the left and right arrow keys to select the Main submenu.
4 Use the up and down arrow keys to select F12 Boot Menu.
5 Use the F5 or F6 key to change F12 Boot Menu to Enabled.
6 Press the ESC key to enter the Exit submenu, press the ENTER key to Exit
Saving Changes. Press the ENTER key again to select Yes. The system will
reboot.
7 After rebooting, when the eMachines logo shows, press the F12 key to
open the Boot Menu. Here you can select which device to boot from.
8 Use the arrow keys to select the IDE1*, then press the ENTER key. Windows
will be installed from the recovery disc.
9 Insert the second recovery disc when prompted, then follow the onscreen
prompts to complete the restore.
10 Remove the recovery disc from the optical drive once the restore is
complete. Do this before rebooting your computer.

Hope this helps!

Takasashi