So, from searching around & a bit of my own knowledge, here are some solutions to try (if people on this thread want to try these, and post back, we might be able to reach a consensus here):
1) Do a clean install of 337.88
- Windows XP:
NVIDIA DRIVERS GeForce 337.88 Driver
- Windows Vista/7/8:
NVIDIA DRIVERS GeForce 337.88 Driver WHQL
- Windows Vista/7/8 laptop:
NVIDIA DRIVERS GeForce 337.88 Driver WHQL
When installing, choose 'Custom Installation', tick the 'Clean' box, and then install. This should erase all existing nVidia drivers before installing and make sure it's all properly set up.
2) Try this fix:
Ultimate Fix: Display Driver Stopped Responding and Has Successfully Recovered NVIDIA & ATI
This seems to just be fixing a corrupt file that's not installed properly through the installation process, suggesting that the installer is broken in some way.
3) Try this fix:
Watch Dogs keeps crashing my nvidia driver :: Watch_Dogs General Discussions
This sets the power management to 'Maximum Performance', which could temporarily improve timeout issues.
4) Try these fixes:
FIX for stuttering/lag (Nvidia and AMD) or even BSOD (with AMD video card). MUST READ! :: Watch_Dogs General Discussions
More suggestions for nVidia and in-game config.
5) Increase your PCI bus timeout to 128
If all else fails, this should be in your BIOS options somewhere, it should be labelled "PCI Timeout" or "PCI Master Bus Timeout". Not all BIOSes have this option (e.g. I'm on a Lenovo motherboard which doesn't seem to have it), although it could be hidden in a sub-menu somewhere (e.g. "Advanced PCI options"). It probably defaults to something like 32, increasing it to 128 should be plenty.
Hopefully one of these has some effect. I'll also try these on my own PCs a bit later.