For a while now I've had an on-again-off-again opengl issue.  Mostly it works fine, but sometimes it's not there and software opengl is running instead (with a hefty performance penalty).

Today hardware opengl is off and I can't find any way to turn it back on.

I'm running a Dell M4300 with XP and SW2009SP4.  The issue first reared it's head with SP2 and had been behaving itself with SP4 until today.  I'm running the SW tested driver, previously a reinstall of that and a reboot or two would help.  But not today.

What else can I check?

I've reinstalled the drivers twice and rebooted half a dozen times.  No improvement.  I repaired the solidworks installation, again no improvement.

Are there any checks I can run on my graphics card?