Got an odd problem with my new build

Its a shuttle SN25P
AMD A64X2 4400+
2x1Gb DDR400
SATA2 250Gb Seagate HDD
PCI-E 16x 512Mb Ati Radeon X1300 graphics

Now it usually boots and runs fine, but every now and then on a reboot or cold boot i will get the message on my TFT that the graphics mode is not supported or sommit along those lines.

Any ideas why it does it? Why only randomly? A way to fix it at all?

Cheers

does it still boot up ok ?

my brothers compy does that right up untill it gets into windows and the resolution changes up from the standerd one win boots at (640x480? 800x600?)

runs fine tho

i dont know as iv always hit the reset button untill i got a post screen up, still odd that it changes res on some boots.. if thats really what it is