I have a problem with my iMac (2007) the other morning I was listening to music on YouTube and it just quit the Safari application, I closed Skype (which was active) and tried to shut it off....it did not execute the order and I had to doit manually. When I restarted it prompted me this screen:

I posted a help thread here, and they gave me this advice:
As I said in my former Post, put the installer disk inside then shut it down, after this hold the C key when you start up, it should now startup from the CD/DVD, when the installer launched you'll see the menu Bar on top, click on Utilities(pretty sure it is called that way) and select Disk Utilities, it will open, when it is open click on your Hard disk on the left, on the right you'll see 4 buttons, two of them are repair permissions and repair disk, do one at a time, when finished close Disk Utilities, installer will appear again but go back to the menu and click restart.
I proceeded to do so....at no avail.......it showed me once again the above screen...and after that, I turn it on, ear the disc starting to run, and from then on, just gives me a blanc (white) screen and an allarma as there was an imminent Nuclear Attack......(I tried several times, and it is stuck at that screen and allarm)
When I saw the last message, I wrote it down...here it goes:
PANIC (CPU 0 CALLER 0 X 003AB7C3): UNABLE TO FIND DRIVER FOR THIS PLATFORM: "ACPI"
DEBUGGER CALLED: <PANIC>
BACKTRACE, FORMAT-FRAME: RETURN ADDRESS (4 POTENTIAL ARCS ON STACK)
0 X 36a93df8:0 x 128d08 (0 x 3cc0cc0 x 36a93c1c 0 x 131de5 0 x 0)
(there where 4 similar messages...the last one ended in) : BACKTRACE TERMINATED-INVALID FRAME POINTED 0 X 0
KERNEL VERSION: DARWIN KERNEL VERSION 8.10.3: WED JUN 27 23:29"36 PDT 2007; ROOT; XNU - 792.23.3~1/RELEASE_1386
PLEASE HELP!!!
What in the world is happening to my computer? Do you guys have experience with this? And is so...what is it? Major? Minor? Simple? Complex? I probably should take it to a tecnician, but I would like to have an idea first....besfore they understand I don't know much and suggest to sell me parts that are very expensive and probably not even damaged (it happens often down here in Miami, Florida)
If you have suggestions and a solutions I can apply, please let me know....the Install Disk 1 is still in the computer.....
PLEASE HELP!!!
I love that machine......
thanks in advance to you all....
Franco

I posted a help thread here, and they gave me this advice:
As I said in my former Post, put the installer disk inside then shut it down, after this hold the C key when you start up, it should now startup from the CD/DVD, when the installer launched you'll see the menu Bar on top, click on Utilities(pretty sure it is called that way) and select Disk Utilities, it will open, when it is open click on your Hard disk on the left, on the right you'll see 4 buttons, two of them are repair permissions and repair disk, do one at a time, when finished close Disk Utilities, installer will appear again but go back to the menu and click restart.
I proceeded to do so....at no avail.......it showed me once again the above screen...and after that, I turn it on, ear the disc starting to run, and from then on, just gives me a blanc (white) screen and an allarma as there was an imminent Nuclear Attack......(I tried several times, and it is stuck at that screen and allarm)
When I saw the last message, I wrote it down...here it goes:
PANIC (CPU 0 CALLER 0 X 003AB7C3): UNABLE TO FIND DRIVER FOR THIS PLATFORM: "ACPI"
DEBUGGER CALLED: <PANIC>
BACKTRACE, FORMAT-FRAME: RETURN ADDRESS (4 POTENTIAL ARCS ON STACK)
0 X 36a93df8:0 x 128d08 (0 x 3cc0cc0 x 36a93c1c 0 x 131de5 0 x 0)
(there where 4 similar messages...the last one ended in) : BACKTRACE TERMINATED-INVALID FRAME POINTED 0 X 0
KERNEL VERSION: DARWIN KERNEL VERSION 8.10.3: WED JUN 27 23:29"36 PDT 2007; ROOT; XNU - 792.23.3~1/RELEASE_1386
PLEASE HELP!!!
What in the world is happening to my computer? Do you guys have experience with this? And is so...what is it? Major? Minor? Simple? Complex? I probably should take it to a tecnician, but I would like to have an idea first....besfore they understand I don't know much and suggest to sell me parts that are very expensive and probably not even damaged (it happens often down here in Miami, Florida)
If you have suggestions and a solutions I can apply, please let me know....the Install Disk 1 is still in the computer.....
PLEASE HELP!!!
I love that machine......
thanks in advance to you all....
Franco