I just switched an Acer Aspire 3630 from XP to Fedora 16 beta.
NB: I had the same problem under fedora 15.
I did a yum update so I'm very very close to the official fedora 16 coming out in 2 days.

problem: Gnome 3 goes to non 3D interface (not a big deal for me).
bigger problem is I can't play 3D games on it either (I tried Nexuiz, and it says my hardware does not do 3D).

When that machine was running XP, it did 3D decently well.

So it seems it's a driver problem.

I used lspci:
I searched my pc model (3634WLCI) in google, and think it's got an M661 graphic card.

I don't have much clue what to do next. Hardware drivers is not my thing ...

The SIS drivers are from 2002; I doubt they would run on a modern system. If you need 3D, I suggest you continue to use Windows XP.

Yep, I used to have a laptop with that chipset, I sold it and bought one with an Intel chip. The SiS chipset wasn't even good under XP for me, I had all kinds of problems with tearing and flickering.

Thanks macemoneta and elliott678.

I'll have my younger son use it for libreoffice / firefox / gimp etc ... then.
And maybe convert it to a file server / firewall etc ... when he wants a more powerful machine.
Right now that laptop would be worth around 50 euros, so I'm not thinking about selling it.

Anyway, thanks for the advice, I'll stop worrying about running 3D on it.