Hi FRIENDS, Here´s my problem:
My computer is: Main Board Asus P8B75-M, CPU I5, 4 Gb Ram, OS Win7 x 64.
It has video on Board working fine, I´ve tried to install NEW Video Card Nvidia GT-630 from Gigabyte, all was ok till i tried to install driver from the DVD, at first it checked compatibility, all was fine, starts to install, then stopped and writes ERROR cant finish! no explanations..., I´ve tried a newer display driver dowloaded from the gigabyte´s web site, same results... checked the BIOS everything´s fine, updated it, same results, I am out of ideas!!!!
Please help, I want to send the new Video Card to the garbagge, but wife keep telling me, the money it coast!!!
 WELL, this is the right place. It helps if you give details about the new video card. Also,you said  the motherboard has a built-in video. Right?
What does your documentation  says about the installation procedure?

Sometimes the install is rather odd, depends on the card.

Here is a typical procedure for certain video cards
1. Do not insert card into your PC yet.
2. Change the existing drive to generic VGA. reboot to make sure.
3. Power down the PC again  and install the new card.
4. Reboot, do not let Windows find a driver for the card.
5. Run Setup form  the CD that came with the card.

Of course, not knowing all the details, I don not know if this applies to your card.
Failure to use a special procedure, if required, results in a failed install. This has been documented elsewhere. The issue often is the user didn't read the instructions.

This is my attempt to help. 

Thanks for ur answer, i really need it:

The video card is the Nvidia GT-630. manufactured by Gigabyte, PCIexpress 2.0, 2gbytes and instruction for installation were the most simple:
1 Unplug the computer
2 Insert the card in the PCIexpress socket
3 connect the appropiate cables
4 Turn the computer on (it will be in VGA generic mode)
5 Insert the driver disk
6 Follow the screen instructions and so on....

I did all that way, and it started the installation programm, all by the rules, checked the system, and found it compatible, but in a moment later stopped and writes unexpected error cant install.

I´m telling you I´ve installed several video cards before in different more complicated ways, like ATI cards, but never had this kind of problem.
I´ve read all the manual in the DVD installer and they dont advice any kind of special type installation, I´ve checked the BIOS of the Main Board, for some kind of special settings, but there is nothing there.

I´ve tried some different ways of installing but always the same , big ERROR .

In resume I´m entangled in a bad way and really dont know what else to do.

There is some detail I´ve remember, could be related : about 3 month ago  i´ve dowloaded from the windows update, an update for the build in Intel video graphics, and after download it started to install as always, automatically, and before it ended, stopped and send an error message."it cant update the driver", I tried again, and the same result as before, ¿could be the problem is something bad working in my Main Board?

Thanks again for ur attention.   diegog, Your problem is not as rare as you might think. Some stuff not there just does not work well with other stuff.

I believe order of install is the issue. The New card has to be early in the install.

Here is a method that has worked for others and myself. Get a free copy of some backup  software, and external drive and a partition tool.

Backup your  stuff, re size  and create a new partition. Next do a full install of the OS on the new partition. Can you do this? Yes, you can. And it is legal. Next Try installing the new video care before you do the chip drives, Yeah, sounds crazy. Worth a try.

Or, just to test you sanity, try a live CD like Mint Linux or Slackware  or what Linux you like. Often the Linux auto detect works very well.  Helps prove if the devices are really hardware conflicting or not.thxs for ur input!!!
Sounds logic. I´ll give a try, could I use a "Virtual Box" or "Virtual machine"  to do the experiment???
I do have Ubuntu, could try too
thanks againThe reason for using a "live" CD is to check your hardware without making any changes. When Linux boots, it does a broad RANGES of tests to identify your hardware. If there was a real physical conflict it may report such.

It is good news when the Live CD shows a nice desktop
It swill make you have a better state of mind.

No, I don't mean you have to give up Windows and go to Linux.
OK I´m trying to find those live CD.

I only was meaning to use Ubuntu in a virtual box or virtual machine, never mind...

Thanks, I´am working   I´ve used the first part of ur advice, and it worked well, the video card is working well, now i´m restoring all my files.
Thanks a lot for ur help,.
!!Problem solved  !!!