|You don't press a key for drive diagnostics on an Acer laptop. There is no drive diagnostics on it. only Dell laptops have built-in drive diagnostics.|
To test your hard drive you have to download testing software for DOS from the hard drive manufacturer using a working PC, then create a bootable CD from the downloaded ISO file. You then use that CD to boot your Acer laptop from and the testing software will appear on the screen.
You can use SeaTools for DOS to test any brand of internal hard drive. Get it here (click "Downloads"): http://www.seagate.com/support/down...
Then install IMGBurn from here: http://filehippo.com/download_imgburn/
Use IMGBurn to create a CD from the SeaTools for DOS ISO file, then boot your Acer laptop from that CD.