Hi Phillipe,
If I understand you right:
You had a system that was working, but it had poor specs, and you wanted to upgrade it.
A friend gave you more hardware so you could upgrade.
You mixed and matched the parts together to build a better system, but you couldn't get it to work (did it even power up?)
You re-built the system with the old config, and now it no longer works either?
This unfortunately can still be a number of issues that would be diificult to limit down without some replacement hardware for diagnostics. Also, if you are not familiar with ESD (Electro Static Discharge), then simply touching one of your components may have 'blown' it. Especially if its memory or a CPU.
[For those of you who are familiar with ESD, I have seen some people who can lick a stick of memory while walking across a carpet, and I have seen others who can't even move a piece of memory through thin air without blowing a chip unless they are grounded - its a very personalized thing :eek: ]
The best thing I can say is you need to start with bare minimum components and get them working one at a time. You have to start with a working MoBo, CPU and memory [and the PC speaker connected so you don't have to worry about Video at first].
Get those three things going... Just the bare minimum. Make sure the power supply initializes, and the fans run, and that the system continues to run (not much help if an AT power-based system, but very critical in ATX powered boxes.)
Then add the video card until you get one working. Unfortunately, sometimes its a cascade effect you would never guess....
[INDENT]I know of someone who just last week was unfortunate enough to blow his Power Supply. Fried and everything, complete with black smoke, the smell of ozone and flashing lights. Well, it took him TWO days to diagnose the issue, and not without my help. But though the CPU and memory apparently survived the power hit when the MoBo fried.... the AGP Video Card did not - but we had NO idea at first... because the video card powered up on the bus, and gave him video and configured the new drivers. Problem was.... he could not add another single card to his new Mobo (no Network... no sound.... no nothing) until we finally decided to remove the Video card on a whim (apparently, it was corrupting the onboard MoBo power when plugged in, so nothing else could sync on the PCI bus).[/INDENT]
Just an example of how difficult it can be to identify bad hardware. And like I said, even just moving a component through the air (in the right conditions), can fry a component.
I will presume you verified that the monitor cable is plugged in tightly and the card is seated firmly. The next thing I would try is an alternate PCI Video card until found one that works - just to confirm which part is giving me the problem. I know I have extra PCI vids lying around, but don't know if that helps you.
Hope the rest of the info is useful, and good luck!