>but it just stay stuck with a question mark inside a folder
The blinking question mark means that the firmware could not find a valid OS on your startup disk. The likeliest possibilities are your OS has become corrupted or the harddrive has failed.
If you have a second Mac computer, you may want to try to copy over as many files you can. One way is to use target disk mode.
Another way to recover any data on the harddrive, you can try removing the harddrive from your system and placing the harddrive in an external harddrive enclosure. You may be able to read the data on a second computer.
For slot loading machines... Try holding down the option key then power on. This brings up the startup manager. Click on your hd. Click on right arrow key.
Try re-installing the os.
Sometimes if volumes don't appear in Startup Manager (what you get when you hold down the Option key at startup), you need to reset the Mac's PRAM, NVRAM, and Open Firmware. Shut down the Mac, then power it up, and before the screen lights up, quickly hold down the Command, Option, P, and R keys, until the Mac has chimed twice more after the powerup chime. Then, before the screen lights up, hold down Command-Option-O-F until the Open Firmware screen appears. Then enter these lines, pressing Return after each one:
"The reset-all command should restart your Mac. If so, you have successfully reset the Open Firmware settings."
How to eject a cd from the internal cd drive:
List of devices:
List of variables:
( nvram is the equivalent Mac OS X terminal command. )