Assassin's Creed One Crashes on Load Screen

The first few times I played it, it worked fine. Stuttered a little on the loading/splash screen with the particles all flying around, and every now and then during gameplay, but otherwise I could play fine on full graphics.

However, it now just freezes on this splash screen, and I can't progress.

This happened around the same time as the new nvidia drivers came out. As such, I upgraded, just to see if it helped. It did not, so I have rolled back (which also didn't help). I also noted that with the new drivers, my system didn't seem to use my 640m, instead using the intel graphics (at least, HWinfo or furmark didn't recongnise it).
The only other updates to occur have been automatic windows updates.

I have a Geforce GT 640m and an i7-3630Qm with 8gb RAM. I am running windows 64bit. My computer is a Horize W25b (a custom clevo, specific to the builder).

From google, I saw that this problem often occurs due to ubisofts client trying to access the internet, and flicking off the internet should fix it. However, this has not worked for me, and I haven't been able to find another fix.

I have wondered if optimus is switching to the 640m straight away, and hence the intel graphics can't handle the load screen. However, it loads on my desktop (which only has intel integrated graphics).

It's odd given it loaded each of the first few times I played, and suddenly does not at all. Has anyone else run into this, or does anyone have a suggestion?