Having fun with their latest update? Before getting into the new build here the update seen during the summer months caused quite a few problems to come up the last time I ran HL2 or EP1. Just installing those on the new build on both Vista and XP saw a similar problem. But I haven't quite have had a chance to try either lately. Hopefully you won't have to reinstall it to see the driver problem corrected. Have you rebooted since to see if it persists?
Don't feel bad! $)%)# ggrrrr..! When installing HL2 on Vista along with HL1 and EP1 the Steam updated engine saw some problems there too at first.
Lately I've been tied up just getting everything up and running on a new build here seeing video and sound software/driver problem with the newer cards like a DX10 capable video card and a Creative nightmare seeing their latest XP update turn out to be a web updater for Vista driver set. What"s this? I select XP Pro/Home on the OS selector there to see a Vista update download and install! GGrrrr..!
As you can see Steam isn't the only one goofing up on updates! I've seen XP drivers work on Vista but Vista on XP? I'll be running HL2 again as soon as I finish up a project I started on the old build carried onto the new one here. I'll have a chance to see if the Steam engine runs or doesn't?