I don't know what your specs are, but here are Half Life 2's the minimum spec would be a 1.2GHz powered PC with 256MB RAM, Win 98/ME/2000/XP and a DirectX 7 compatible graphics card.
But for those who want to see the game running in all its glory, be prepared to spec up to around a 2.4 GHz machine, with 512MB RAM, Windows 2000/XP and a DirectX 9 capable graphics card. The G/C should be at least 128MB....TT
------------------ System Information ------------------ Time of this report: 1/15/2005, 16:50:04 Machine name: AMD Operating System: Windows XP Home Edition (5.1, Build 2600) Service Pack 2 (2600.xpsp_sp2_rtm.040803-2158) Language: English (Regional Setting: English) System Manufacturer: SOLTEK System Model: 75FRV BIOS: Version 07.00T Processor: AMD Athlon(tm) XP 2600+, MMX, 3DNow, ~1.9GHz Memory: 512MB RAM Page File: 263MB used, 987MB available Windows Dir: C:\WINDOWS DirectX Version: DirectX 9.0c (4.09.0000.0904) DX Setup Parameters: Not found DxDiag Version: 5.03.2600.2180 32bit Unicode
Judging from what Steam said, and the fact that I couldn't find anyone on Google who had actually fixed the problem despite doing some of the measures suggested, my advice would be to be patient and wait for the patch. Frustrating, but I think it's what I'd do.