Blue logon screen ?

[Loper]

...no graphical boot screen, with a new mother and an AMD Duron.

More details on your hardware, please. Chipset and/or brand/model of MB. Video card. If a card is in the PCI slot adjacent to the AGP slot, move it if you have a slot to spare; it shares an interrupt with the AGP slot which can confuse the system or slow things down.

Also, check your BIOS settings. I have sometimes found that the BIOS default is labeled VGA graphics from PCI or something similar. Change that to AGP -- it's possible that the logo graphics are being sent to the wrong slot. Check the other VGA & AGP hardware setting as well.

[oscar]

Thanks,
the mobo is ECS K7S5A Pro, chipset SIS 735
The video card is Riva TNT M64 AGP
The bios is AMI and unfortunatelly there is not anything like VGA graphics from PCI

[Loper]

The BIOS is AMI and unfortunately there is not anything like VGA graphics from PCI

Actually, there is. I was thinking Award; It's slightly different under AMI.

Got to the BIOS PCI / Plug and Play menu -- all three items need changing from the default:

Set PnP OS = NO (not needed for Windows either, despite the manual).

Set Primary Graphics Adapter = AGP.

Set Allocate IRQ to PCI VGA = NO.

These changes are needed anyway, so they can't hurt. I have used Knoppix with great success on this MB. Good luck!