help Will i lose my files-Folder with questions mark start up issue!!!

I know this is probably the wrong area to post in but either way , im new to macs and did something stupid ive read about how to fix it but im hesistant because i dont want to lose just 1 file i have and want to know if this sign f'ed up my files before i do anything plz need help!!!

I Did--lose Everything

I had the question mark folder and tried everything suggested in trouble shooting in the little book to start up my computer so I could at least save everything. Nothing worked. I took it to the Mac repair shop (authorized, not Genius Bar) and when I picked it up they told me they had to install a new hard drive. So if you should have to do that make sure you ask them if they can try to save your files. Also ask them if they can give you the old hard drive. I am not sure they can, but it is worth a try.

It might be worth your while to buy an external hard drive. It will automatically back up your files, once a day, once an hour, etc. That's what I do now.

Try booting up from your restore disk first and run disk utility from the menu bar when the install screen comes up

Do that first