Verified answer

Because you can't boot from CD's doesn't means your hard disc is f*ed up.

Go to your BIOS settings and see if the DVD-CD drive is set as first to boot with; good luck.

I am sorry to report that there are so many different issues which could cause this that it is impossible to properly assist you in this type of a forum. I recommend you either take your system to a reputable repair shop or use a technical help forum on the web where expert volunteers walk you through steps to diagnose and fix the system. The first costs you money, and the second costs time and maybe parts. I will provide a few forums you can select from:

http://www.microsoft.com/communities/newsgroups/en...

The first is to the Windows Vista Hardware and Device forum. You need a Passport or credentials to post your own question. If you have a Hotmail or Windows Live Mail account that is your Passport. Just enter your email account address and its related password and then you can post. If you do not have one of these email accounts you do not need to open one, you can attach any valid email account when creating your credentials. Simply click the Sign In button in the upper right corner of the screen, then click the link to create your Passport at the Sign In page.

http://www.bleepingcomputer.com/

This second is a third party independently owned technical help forum. Again, you can read as many posts as you like but to post your own question you will need to register.

http://groups.msn.com/FreewareandShareware/welcome...

This last link is to a forum which also offers a Chat room for individual assistance. Check each out and decide which you feel most comfortable with then either get credentials or register. Good luck and I hope it is something small, so you can get up and running again quickly. Please have a nice day.

Sorry,I have to disagree with Serenity. You know those forums you go to Serenity? I'M ONE OF THOSE GUY'S! (Yes, I take offense to your answer!)

1.What is the condition of the inside of the computer? Is it dirty? Is the power supply dirty? Most of the computers in my shop are in this condition. Owners neglected to clean their computers on a regular basis.

All it would have taken, was a can of compressed air for computers!

Dirt/Dust/Animal Hair/People Hair/Lint/Food Crumbs/Carpet Deodorizer/Dead Bugs/Spider Webs, you name it, gets sucked up in the computer.

This foreign debris collects on the processor fan, and it's heatsink. Also collects on the various motherboard components. This foreign debris is a Static 'magnet'. It can short out components inside, by leading electricity from component to component.

Also when a power supply collects this debris, it can do the same. Mostly, the power supply fan collects the debris, and the cooling capacity drops tremendously. When the power supply heats up beyond the manufacturers parameters, it tries to put out more power. Heat=Wasted Energy. When the power supply reaches it's limit, components inside start to fail. The first ones to usually go out, are the Electrolytic Capacitors. When they do, a weak voltage rail is the result.

2. A processor requires a steady, clean supply of electricity. It can't vary by much, as the tolerance range is very small. If it does vary too much, the BIOS program turns it off. The BIOS program, on the BIOS chip, on your motherboard, will also turn the processor off if it gets too hot. The negative value is what the BIOS program reads.

But, if the voltage doesn't vary too much, the processor will start 'acting weird'. This can cause a hardware problem, that will mimic software issues.

A power supply with a weak voltage rail, will cause problems that mimic software problems.

Electrolytic Capacitors that are weak,and getting ready to fail, will also cause these problems. The ones around the processor, are the ones specific to this problem. Again, the processor requires that steady, clean supply of electricity, I mentioned.

Capacitors around the processor are Voltage Regulators. IF JUST ONE goes bad, the processor 'falls on it's face'.

3.Lastly it could be the harddrive. If you hear it making a whining, metal to metal sound, it's on it's 'last leg'.

(I have some 'IT' men down at the shop. I messed with their heads one day. They had two computers that would not boot up. Went to the computer manufacturer 'splash screen', and stopped. They worked on these two computers for two days. When they went to lunch on the third day, I slipped over, and put a known, good, power supply in. Booted right up. When they came back from lunch, the computer was off. I reached over and pushed the power button on. Boy, were they MAD! lol! )

Edit:

1.http://en.wikipedia.org/wiki/Capacitor_plague

2.http://capsmod.net/forum/viewthread.php?tid=19&ext...

3.http://www.youtube.com/watch?v=KN6_-8fYHo0&feature... (Starts at 0:04)

I don't know much about computers but did have a problem that sounds the same a while back. My hard-drive had completely crashed and had to be replaced by the manufacturer. I lost EVERYTHING I had on my computer. Good luck!!