Just means you havent installed Asus Express Gate on to the Primary HDD.
If you're not going to use it and want to get rid of the message. Go to your Bios setup. Go to the last tab, and disable Express gate. As you say "followed by the motherboard's logo, then the boot up process begins" - This is normal. A bit info.here for you click here
I don't think this is the reason for your PC "crashing" - I think you need to look elsewhere.
You could have a problem with "overheating" if it occurs whilst using.