I got a new computer a few weeks ago and the only thing it cant do is minecraft. I know minecraft is single thread but with optifine it can be multi-threaded. Now this is where the problem starts as I cant set minecraft to multicore without it crashing. I'm using a ATI radeon x1200 series on a laptop so replacing it doesnt seem like an option. Also buying a new computer is out of the question as of now. Heres the crash report. I hope it helps.
 Minecraft Crash Report ----
// My bad.

Time: 8/29/12 12:20 AM
Description: Unexpected error

java.lang.RuntimeException: org.lwjgl.LWJGLException: Could not create context (WGL_ARB_create_context)
   at WrUpdaterThreaded.createUpdateThread(WrUpdaterThreaded.java:69)
   at WrUpdaterThreaded.delayedInit(WrUpdaterThreaded.java:40)
   at WrUpdaterThreaded.updateRenderers(WrUpdaterThreaded.java:171)
   at WrUpdates.updateRenderers(WrUpdates.java:64)
   at avb.a(RenderGlobal.java:1500)
   at auw.a(EntityRenderer.java:1295)
   at auw.b(EntityRenderer.java:1045)
   at net.minecraft.client.Minecraft.J(SourceFile:607)
   at net.minecraft.client.Minecraft.run(SourceFile:535)
   at java.lang.Thread.run(Unknown Source)
Caused by: org.lwjgl.LWJGLException: Could not create context (WGL_ARB_create_context)
   at org.lwjgl.opengl.WindowsContextImplementation.nCreate(Native Method)
   at org.lwjgl.opengl.WindowsContextImplementation.create(WindowsContextImplementation.java:50)
   at org.lwjgl.opengl.Context.<init>(Context.java:120)
   at org.lwjgl.opengl.Pbuffer.<init>(Pbuffer.java:238)
   at org.lwjgl.opengl.Pbuffer.<init>(Pbuffer.java:200)
   at org.lwjgl.opengl.Pbuffer.<init>(Pbuffer.java:176)
   at WrUpdaterThreaded.createUpdateThread(WrUpdaterThreaded.java:58)
   ... 9 more

Relevant Details:
- Minecraft Version: 1.3.2
- Operating System: Windows XP (x86) version 5.1
- Java Version: 1.7.0_06, Oracle Corporation
- Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
- Memory: 452656264 bytes (431 MB) / 519110656 bytes (495 MB) up to 1037959168 bytes (989 MB)
- JVM Flags: 2 total; -Xms512m -Xmx1024m
- LWJGL: 2.4.2
- OpenGL: ATI Radeon X1200 Series GL version 2.1.8545 Release, ATI Technologies Inc.
- Is Modded: Very likely
- Type: Client
- Texture Pack: Default
- Profiler Position: N/A (disabled)
- World MpServer Entities: 1 total; [atg['dartflames'/114, l='MpServer', x=8.50, y=66.62, z=8.50]]
- World MpServer Players: 1 total; [atg['dartflames'/114, l='MpServer', x=8.50, y=66.62, z=8.50]]
- World MpServer Chunk Stats: MultiplayerChunkCache: 0
- Forced Entities: 1 total; [atg['dartflames'/114, l='MpServer', x=8.50, y=66.62, z=8.50]]
- Retry Entities: 0 total; []