have you added any new hardware latley? As bizarre a question as this might sound it is actually relevant.
Recently i added my 7th IDE HDD When i did my machine would do exactly the same. The pc would not crash or freeze in any way, it wold just continue to sit there with the line moving accross the screen from left to right... When i removed the 7th drive the pc booted fine? So i tried adding a DVDRom and the same problem again, so i tried a different configuration, and still it happended again. I eventuall looked this up and thought it was a power issue. However i hav a 550w power supply and that is ample for 7 HDD.
My point is if you have just made a recent hard ware configuration change make sure you undo the change and check again. For example if you have added a slave drive and have the jumpers incorrect this can some times cause this prolem etc etc etc.
If not never mind was just an idea as i have this problem with adding 8 devices on my 4 IDE channels.
