My old Nvidia 8800GT 512 card crashed and I had to buy a new card. Based on advice in this forum I purchased the GeForce GTS250 512 card. My system is an older one using a dual core 6850 chip at 3.00 Mhz. Thew new card was installed and new drivers updated and after a few flights I got the nv4_disp.dll BSOD. After some research I uninstalled the drivers, used CC Diver Cleaner and also used a registry cleaner. I installed the Nvidia driver again, requesting a clean install and then updated to the recommended FSX settings using Nvidia Inspector. Everything looked ok for a few days but now the BSOD is back. Seems to happen mostly when I go to outside view, if I stay in the VC I seem to be OK.System Windows XP, 4GHZ ram, 3GB switch enabled. Flying mostly FSLabs Concorde. No previous issues at all with this problem and my old 8800GT card.Any help greatly appreciated.Mark.

There have been tons of articles on that specific error over the years. Unfortunately there has been no *specific* solution other than trying different drivers. Sometimes the *latest and greatest* driver isn't quite right for older systems/cards. Drop back a driver version or two and try again - using the uninstall - clean - reinstall method.It will be hit or miss but keep trying.Vic

Hi Mark,Never, ever, run a registry cleaner in between uninstalling and reinstalling drivers. It can remove now redundant but neccessary references that may be needed. I would never use one at all, but that's my opinion only.Most reg. cleaners have backup, I would replace the removed entries. Run it again if you want, when everything is in place and sorted.http://chris.pirillo.com/are-registry-cleaners-safe-to-use/I agree with Vic also.I would have uninstalled the drivers and also the video card in Device Manager first, then shut down and replaced the card and let Windows detect card on start up, then install new drivers.You could try this, remove the card from Device Manager, ie. uninstall it. Then reboot and let Windows do the rest. It will detect card and install drivers for you.next, reinstall Direct x 9. Ron.

A thread about this here;[/url]http://www.simforums.com/Forums/nv4-dispdll-fsx-blue-screen-crash_topic36646_post214715.html?KW=nv4%5Fdisp%2Edll#214715

OK thanks, will give it a try.Mark.

As Nick explains in the thread, Nvidea's later 400 series drivers are not really aimed at XP 32 bit systems as support for this platform is ending soon.If all else fails, try the same drivers you used for the 8800.Ron.

As Nick explains in the thread, Nvidea's later 400 series drivers are not really aimed at XP 32 bit systems as support for this platform is ending soon.If all else fails, try the same drivers you used for the 8800.Ron.

I think I may have it fixed now. I ended up following a guide from someone who suggested turning down the clock speed by 10 - 20%. The impact on my system was zero so hopefully this will fix the problem.thanks,Mark.

Unfortunately the thing crashed again....always on the ground as Nick suggests. If the only way to fix it is to upgrade to W7 64 bit can that be done with an upgrade license from Windows XP ? I am reading conflicting information on this.Mark.

You can not upgrade from Xp to W7. You have to do a fresh install.Now, whether you can use a valid copy of XP to get upgrade "PRICING" on W7 - I'm not sure - but I do know you can not do an inplace upgrade. You must install W7 and reinstall all applications.Vic

OK, thanks.

Well decided to roll back the drivers to 186.18 and so far so good. Still some pauses I don't like but still working on it with Nhancer.Mark.

This nv4_disp.dll blue screen post helps you to find more info about the problem....