My iMac is getting stuck at the white Apple logo screen and won't go any further. I've tried SMC reset and also pram reset, and neither really worked out for me. It's getting me frustrated because I need to type up an essay >.<
Could be a dead HD, that was the case when I had a similar issue. You might want to run a hardware test, you should have gotten a disk for that with your computer, or it might be in the recovery partition for Lion machines. If you have up to date backups you should be fine but you might need to pay for a new HD if you're out of warranty.