Can't run WebGL at all - ideas?

Symptom: I go to Chrome Experiments, click (e.g.) “Traveling Wavefronts” or “Solar System Explorer”, click “Launch Experiment”. A window opens. On top of the new window, a dialog box says “Your browser does not support WebGL”.

Hardware: Dell Inspiron 1520, Core 2 Duo T7500 2.2Ghz. GeForce 8600M GT.

OS: legal Windows XP SP3 with all mandatory updates and many of the optional updates.

Driver: updated today, to the latest version on the Dell site for this hardware. The NVIDIA control panel says “ForceWare 174.31.”

DirectX: 9c, all latest updates from the Microsoft site as of today.

Browser: Chrome. About box says I have the latest.

Thanks in advance for any help …
Jeff

OK, apparently the “latest” NVIDIA driver on the Dell site is ancient. I found this in the blacklist rules:

{
  "id": 14,
  "description": "NVIDIA drivers older than 257.21 on Windows XP are assumed to be buggy.",
  "cr_bugs": [74212],
  "os": {
    "type": "win",
    "version": {
      "op": "=",
      "number": "5"
    }
  },
  "vendor_id": "0x10de",
  "driver_version": {
    "op": "<",
    "number": "6.14.12.5721"
  },
  "blacklist": [
    "all"
  ]
},