Posted 23 April 2006 - 11:08 PM
Some computer fans do that on purpose. They often have a single fan on the back with a shroud over the processor. (Maybe another on the power supply) On bootup, they rev, then calm back down to a slower, quieter speed unless they are needed to dissipate more heat, and they'll speed up a bit.
But the video sounds as if you've got either a bad video card (or onboard video), or the drivers have become corrupted. When you boot into Safe Mode, your video drivers aren't loaded and you're seeing basic VGA - 640 x 480 x 16 colors. Open your Device Manager and see if there are any warnings - yellow exclamation mark or question mark. If it's a separate card, you should have a disk for the drivers so you can re-install them. If it's onboard, it would either be the motherboard disk or if a branded computer like HP or Compaq, maybe on a driver disk.
If not, give more info about the machine or the video card and we'll see what we can do to find drivers.
If the video card is separate and has its own fan, you need to open the case and see if it's working OK. Video card fans often last less than a year and it will overheat and would probably already be on its way to being toast.
If it's onboard video and it's failing, you might have to see about adding a new video card and disabling the onboard.