Hi Cfor, Noises from inside your computer can come from any of the cooling fans, (usually the processor fan, power supply fan or in more recent machines the graphics card fan), or from the hard drive. Noises together with boot problems makes it most likely to be the hard drive. Your first priority is to back up all your important data. Next remove the case cover and see if you can confirm where the noise is coming from. My favorite method of doing this is to use a rolled up sheet of paper as a stethoscope. Put one end to your ear and use the other end to localise the source of the noise. If the hard drive is failing you will have to fit a replacement. A 30G drive is about £50 from Dabs (click here) or Ebuyer click here). The way you tackle the replacement depends on you. You can reload windows and your software from their installation disks, or you can use a cloning utility. What I do not advise is waiting until the drive completely fails and the data is unrecoverable.