The executable is "java.exe," "javaw.exe," or "javaws.exe." Haven uses Java Web Start--javaws.exe. Most of the modded clients use the standard edition launcher, java.exe or javaw.exe (pretty much the same thing; differences are technical as far as most users are concerned).
There's another thread here on this. I'll see if I can find it and link it here. I don't use Nvidia cards much, so never do recall what needs to be done.
edit: to note, the above post is really the best thing, but do it through your BIOS, not in Windows, so it won't even boot and save you some power and boot time.
2nd edit: ok, found one of the links I was looking for.
viewtopic.php?f=42&t=50999#p674822 It has a screenshot for those that aren't familiar with doing this, but otherwise it's exactly as I stated.
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