Can't get crates on Win 7 (but could before now)

I can't get a new crate on my Win 7 machine. rustup works fine (so the network's ok), but cargo check fails.

R:\rs\myapp>rustup update stable
info: syncing channel updates for 'stable-x86_64-pc-windows-msvc'

  stable-x86_64-pc-windows-msvc unchanged - rustc 1.24.0 (4d90ac38c 2018-02-12)
R:\rs\myapp>cargo build --release
    Updating registry `https://github.com/rust-lang/crates.io-index`
warning: spurious network error (2 tries remaining): unknown certificate check failure; class=Net (12); code=Certificate (-17
)
warning: spurious network error (1 tries remaining): unknown certificate check failure; class=Net (12); code=Certificate (-17
)
error: failed to load source for a dependency on `regex`

Caused by:
  Unable to update registry `https://github.com/rust-lang/crates.io-index`

Caused by:
  failed to fetch `https://github.com/rust-lang/crates.io-index`

Caused by:
  unknown certificate check failure; class=Net (12); code=Certificate (-17)

Is this likely to be a temporary problem, or is there something I need to do (or can do) to fix it?

Thanks for the link. I installed the update but to do the registry change I had to update IE (which I don't use) since the "easy fix" button doesn't seem to work with Firefox. Anyway it works now.

Hm, it should be broken, may be github revert changes?