Hi. I got my iMac in April '08. 2GB RAM, 250GB storage. That's all I really know and can access. It's been good, very fast until about 20 months ago, slowed down further this year and has continued to gradually slow. Recently it's taken 10 minutes to get going and after a few hours' use started slowing to a standstill. To install new software I also recently installed Yosemite on it, which worked but only slowed down the thing more. Anyway I used it briefly this morning and it was having a good day. Turned it off, came back tonight, and the Apple icon shows as it's turned on minus the loading bar beneath, then after two minutes a "prohibited" sign comes up. I've googled these problems, also searching here and on Apple Support, and learnt how to start the computer with Disk Utility. Verify Macintosh HD, repair Macintosh HD. "Error: Dik Utility can't repair this disk....disk, and restore your backed-up files." I'll do this if I can find someone willing to lend me an external hard drive as I desperately need what I've got on here (over six years of photos, work, software, general life). But I was also wondering if beyond that, whether my iMac is now doomed and has breathed its last. Besides being unable to afford any replacement I have a pressing deadline due tomorrow night, all of whose files are bumping around on a computer I cannot start up. Is there anywhere further I can go with this so I can get back to work? Thanks in advance, it's a great job you do on here.