No Bootable Device -- Insert boot disk and press any key

SOURCE: Acer Aspire One Insert boot disk

well u really cant put in a disc, you said you have the aspire one that means it doesn,t have a disc drive . Thats the way it was made

SOURCE: Acer aspire one mini notebook. NTLDR is missing..

If you don't have documents, pictures, etc on the hard drive that you need to backup, try running system recovery by doing the following (not sure if this works on the version with a solid state drive):
1. Turn on the computer
2. Press and hold Alt + F10
3. Click on Restore System to Factory Default
4. Ensure the netbook is plugged into AC power instead of running off the battery and click OK

* This will return your netbook to the condition it was in from the manufacturer.

SOURCE: NO BOOTABLE DEVICE INSERT BOOT DISK AND PRESS KEY

Do you have your windows OD running? If so, make sure that there is NO CD or DVD Disc left in your CD/DVD Combo drive while you are turning your computer ON. Now, eject the CD or DVD and try to start your computer again.

SOURCE: when I turn on my acer 5115 it says no bootable

it is possible that there is a mistake in somewhere in BIOS. when booting go to BIOS, and look for booting devices. As a primary booting device should be your HDD, or ODD first and HDD second.
apply these changes and see if the problem is fixed.
if it isn't, it is very likely that your HDD is not working anymore

SOURCE: when i turn on my computer. No bootable device --

Check you have no CD, DVD or floppy disks in at the time of bootup. If not you need to contact a local Computer Tech to come out and have a look at it for you.