I have just spent 3+ days with this problem associated with upgrading to W10 ("Asus ACPI driver missing, please install Asus ACPI driver" message). Computer is Eee 1015PED Netbook with W7 starter. The maximum allowable RAM 2GB is installed (suspect not worth upgrading to W10 with less memory). My fix was to reload the computer to original factory settings,
after backing up all user files which will all be lost using this procedure.
1) Boot. Use F2 key (seems particular about speed, approx 1/second till BIOS flash screen appears). Disable Boot Booster in boot section (necessary for next step).
2) Boot again. Use F9 key to access recovery module. Select Recovery option.
Computer will restore to original factory settings in about 30 minutes. The following steps involve drivers specific for W7 (in my case) or the OS when computer was new, and may not work with other OSs.
3a) Next, update all ASUS drivers. I knew the date of purchase of my computer; however the latest version of each driver is on the ASUS support web site:
Asus.com>Support>enter model #>navigate to driver and tools. ***sometimes the ASUS website does not seem to recognize their own models. A Google search for "ASUS (model number), driver download" should get you there.
Select the OS which came installed on the computer when purchased.
Each set of driver files is in a zip file. Unzip/Unpack them and save the associated directory structure. Execute the setup.exe file for each one.
3b) The BIOS file update, also zipped, contains an XXX.ROM file. I'm not keen on updating the BIOS; however it seems frequently that ACPI problems are associated with it based on searching articles on the web. Save the XXX.ROM file to a known location such as the desktop. It may also be necessary to rename the file name to an 8 character (DOS) file name; leave the ROM extension alone. A web search will quickly show this installation is not straightforward. I stumbled upon an extremely easy solution I had not uncovered on web searches. Select:
Windows>Start button>programs>ASUS>ASUS update for Eee PC (
not "live Update"). This opens a BIOS flashing program. Select the option to navigate/browse for the .ROM file you saved. The flashing program will verify the .ROM file and install/flash the BIOS. Mine finished in 5 minutes. The BIOS flashing program looks similar to the last 4 screen shots in the following link (scroll down), however nothing prior to those shots in the pages seemed to work for me.
http://www.asus.com/us/support/FAQ/1008276
4) At this point you now have a factory installation with updated ASUS drivers and BIOS. No W7 updates have yet been selected or installed. If you want to continue with W7 OS, just update through Windows Update. I wanted to install W10. There was not an option to upgrade to W10 at this point, however I searched (Google) for a link to upgrade to W10. That allowed immediate access to a W10 upgrade. Since I had no programs or user files on the computer at that point I was able to select the option to install W10 completely by itself – pretty close to a clean install.
W10 installed fine, and the " ASUS ACPI driver missing, please install ASUS ACPI driver" message is no longer a problem.