|First: have you made any recent changes to your computer? If you have, I suspect that is what has caused your problem. Reversing the changes would be a possible solution.|
If you have had the PC's case open recently, it could be as simple as the video card not being properly seated in the AGP/PCI slot.
If this fault was due to a driver problem, you would get a Blue Screen Of Death. The solution would be to delete the recently added (incompatible or faulty) driver file(s). If you are not getting the Blue Screen, it is unlikely to be a driver file fault.
If you are not getting the Blue Screen, then problem might be solved by temporarily removing the video driver card from the PCI/AGP slot (NB: take appropriate anti-static precautions!) and then booting up, to see whether the basic video drivers that come with Win ME are giving the same fault. They will probably only run your monitor in basic VGA mode, but this test might indicate whether the fault lies in the video card. If it persists, even with the video card removed, then clearly it isn't your video card.
Alternatively, it might be a BIOS error. Try entering the BIOS / CMOS screen (e.g. press DEL during startup) and examining the settings, to determine whether something has altered the video settings. If so, correct them (check the documents that came with your video card - or the manufacturer's website - for the correct settings) and save the revised settings. Then reboot.