Startup problem in XP

I am having HP dc5850, under XP, when I start, I am forced to restart and set the screen resolution in display settings to get back on my feet. (I rule 1027x768). I installed a new graphics card recently (NVidia 7200 GS), put the drivers up to date and uninstalled the drivers of the integrated map of origin (it is an ATI Radeon 3100 integrated). In addition, from time to time, during startup I have the black screen and this message in white text:

"Windows could not start because the following file is missing: \ Windows \ system 32 \ config \ system
restart the installation of Windows XP with the cd rom original installation. Select "R" in the first screen to start repair. " I have not made a changes I type "enter" and the startup continues to take me on the desktop always with poor image quality. So I restart, the resolution rule and it works properly.

Can some one help me whats the problem ?

Thanks

On some PCs with integrated video chipset before inserting a new card must be careful to disable the video chip in bios machine so that when you restart the machine only the card is taken into account by the system. Have you done this? This will explain the "resistance" of the operating system at boot time by default because it is the video chipset to be recognized by Windows and therefore the drivers are necessarily in adequate.

Press F10 to start the PC to access the configuration utility. Search options in the Bios section "PCI VGA Configuration" and set the function to display your video card in device mode or disabling the integrated video chipset. This of course subject to change because I do not have the equipment to test the procedure (one day we will know that a lab worthy of the name and to test the material kindly loaned by the suppliers), but you should get this so if your PC does have a chip built into the motherboard.