Geforce 8400m GS and Windows 7 compatibility issues?

I've recently been having trouble installing official and forceware drivers for my Geforce 8400m GS on my Dell 1420 since I upgrade to Windows 7 32-bit from Vista. When I uninstall my current drivers and reboot Windows fails to boot in normal or safe mode. Generally when I install drivers I reboot into safe mode, run driver sweeper and properly install them. Windows kept freezing at the classpnp.sys file so I changed the file to classpnp.old after some research but it started to BSOD me at the disk.sys file.

So I tried to just outright install the drivers from device manager by upgrading and I would get a message saying Windows couldn't find drivers compatible with any of my hardware. I've done a lot of homework, downloaded countless drivers, disabled aero, used mobility modder, and done just about all I feel I can do to fix this. These drivers worked fine with Vista and I really don't want to downgrade because I lost my product key and disc so that would be a pain. If anyone has had this issue and knows of a driver of modified inf file that would fix this problem I would greatly appreciate it. This has been frustrating to say the least

Nvidia mobility modder or driver max is about all I can think of for this. Between the two you can usually get that driver working.
NVIDIA MobilityModder
DriverMax - FREE driver download program for Windows XP & Vista

I don't know whether it applies in this case, but manufacturers have an unfortunate habit of customizing graphic device IDs, so that the generic nVidia driver installer may not run.

I vaguely recall that I had that problem with an 8200M on my Compaq laptop. I installed the Vuista drivers for it. Afterwards, I received Win7 drivers through Windows Update, and mor recent versions of the nVidia drivers have istalled over the existing drivers with no trouble.

I have a Vostro 1500 with the same graphics card. I used the vista driver. But now it looks like they have one for Windows 7:

Windows 7 32bit driver

There is a software update that you are supposed to install first:
NVIDIA software updates

bobkn said:

I don't know whether it applies in this case, but manufacturers have an unfortunate habit of customizing graphic device IDs, so that the generic nVidia driver installer may not run.

I vaguely recall that I had that problem with an 8200M on my Compaq laptop. I installed the Vuista drivers for it. Afterwards, I received Win7 drivers through Windows Update, and mor recent versions of the nVidia drivers have istalled over the existing drivers with no trouble.

I actually have the exact same card (8400m GS) on my dell laptop have installed the drivers from the nVidia page without a hitch twice for win7. So probably not an issue with the graphic device ID.

I really don't know why you'd be having that issue though. Sorry couldn't be of more help.

I appreciate all the replies very much, and I'm sorry I'm late to respond.

Chuck07 your recommendation seems to have done the trick. I'm not sure if it was the driver or the updated BIOS but everything seems good now. again, I really appreciate it everyone!