Computer won't boot up!

It started a few weeks ago when the computer would start to turn on but quickly turn back off after a few seconds. That problem was solved when we replaced the motherboard to a Asus P5G41-M. It worked for a few days but then started not booting properly. It powers up but doesn't actually boot correctly, nothing appears on the monitor, you can hear everything working, including the fans, but then it just stays on. The monitor has been tested and it's fine. It has an AMI Bios, I used a POST card and it stops at code E0 which says 'The onboard floppy if available is initialised. Next beginning base 512kb memory test.' , no beeps are heard. Could it be the RAM? Any help is greatly appreciated! Thanks.

First off, try removing the floppy from the boot up.......Turn computer on and press delete a few times to enter bios, then search for boot manager or boot priority etc.

After that, i would go for the graphics card. Is it onboard graphics or have you got a pci/agp card?

Remove your floppy,go to the BIOS and set boot device priority and save it.Then restart Your system.