Flashing question folder

Ok this is the 3rd time it happens in a week. Mac just freezes to the point I need to shut down in the power button. When it restarts only a folder with a flashing question mark appear. I repair the permissions with the DVD on the other times cause the HD was shown but now nothing. Disk utility only shows the DVD and nothing else. I also did the PRAM but with no success.
I have a 3 years old iMac with Leopard with all updates almost 125gb of free space a w$ XP partition, 2gb ram and im not sure but i think it has a 2.4ghz.

Any advice suggestions please?

Sounds to me like your hard drive may be failing. Better get your stuff backed up before it dies completely!

- Nick

The flashing folder with a question mark means the operating system can't be found. Usually this is caused by the boot record which records where the system starts on the hard drive. However if your computer freezes so much then like pigoo3 says sounds like a dodgy hard drive failing, or it could be that the system has become corrupt somehow.
Backup your files and re-install your OS, see if it happens again, if it does its new HDD time i'm afraid

- Simon

^They speak the truth. I've been through it once as well.