Asus s56ca showed boot failure/check media cable and does not boot. Then I changed bot sequence to pxe rom first.Then it stops showing the initial asus bios screen, just black and the power switch glo

SOURCE: PXE-E61 Media test failure

That message is when you have your computer set to network boot. You can disable it in the bios or change the boot order to put network after hard drive. Press probably Delete when booting to get into your bios and look for Boot Order.

SOURCE: I have the identical problem as chrisdangelo

hello

I have read your problem and the solution to your problem may be following.

• The BIOS setting may have changed.You can reset the BIOS settings.
• The hard disk type may have changed..look for SATA and ATA.
• Or your window got corrupt.Reset the BIOS setting and reinstall the windows using boot able CD.
• if nothing work out then may be your hard disk connector is loose or your hard disk is gone.

SOURCE: Asus Eee pc 900 can't boot (blank screen)

Just had the same thing happen, and I thought it was the motherboard. Then a tech friend removed the battery and held the power button down. Then he replaced the battery, and it booted up fine! Good luck...

SOURCE: Asus Eee PC 2G Surf netbook fails to boot into OS

 Unfortunately Xandros is a paid (yes, you have read correctly , PAID) Linux distro. You will have to pay to get a Live-USB to reinstall.
Instead you should go here
http://www.pclinuxos.com/forum/index.php/topic,46097.0.html
  and follow the instructions to create your own PCLinuxOS (the one i use) Live-USB. You will need another pc for that. After booting from it all you're gonna have to do is to click on the Install icon on the desktop.

SOURCE: BIOS POST message cannot be displayed and Setup does not run

As soon as your computer turns on, start pressing F2 simultaneously until it enter the CMOS setup.