Chosen Solution

i turn it on and all there is is a blank screen with a folder with a question mark. what should i do?

Dig out the iMac Install CD that came with the computer, put the Install CD in the drive, and it should begin to boot off the CD. Once the computer has booted up from the CD, you’ll have access to a utility that will let you do some simple repairs to your hard drive - either Disk First Aid or Disk Utility, depending on the OS that came pre-installed on the iMac when it was new. The flashing ? indicates that the iMac can’t see a bootable operating system on any attached drive - neither the hard drive, nor the internal CD. The computer will grab hold of the first bootable operating system it sees; in this case, the one on the Install CD. The operating system on the internal hard drive has gotten banged up, to the point where the computer no longer recognizes it as bootable; that’s what you’re trying to fix. Try this first, and let us know whether that gets you anywhere. There are other possibilities if this doesn’t work, but they assume deeper problems; let’s wait to address them until after we know the first fix has failed.