You can take the front grill off, with some T20 screws on the front of the car. You will see the hood release cable, and the mechanism that it attaches to. Just look at it, and you will be able to figure out how to open it from there.
Use pliers and pull the cable...
Use a set of pliers to pull the cable even if the plastic latch is broken...
TAke it to the body shop as they have to do it when a car is wrecked.
A 2004 Buick does not have a speedometer cable. The speedometer signal comes from electronic sensors.
The logical problem - would be a broken speedo cable. The speedo & odometer are both run from the same cable.
Shift Cable
That depends on a few things. If the cable has broken at the release handle, you can use Vice Grips or pliers to grab the end of the cable and pull. If the hood is stuck down you can have a helper pull up on the hood while you work the release in the car. If the cable has broken at the latch consult a pro for help. If you get a helper to hold the the hood release open on the inside and tap lightly, with the side of your fist, on the front of your hood just above the grill. This will usually work if the cable is not broken.
it is next to drivers side on floor in front, take pliers and pull up on cable, this will release hood latch
Remove the grill, cut the cable and pull it with a pair of pliers or vice grips. It might even be possible to push the release on the latch manually, after the grill is removed.
I had a similar problem. On mine, the cable broke right inside the car...right at the lever. There was still plenty of cable sticking out so I just grab it with pliers and pull. If yours is broken in any other place, it will need to be replaced.
It depends on where its broke at. Is the cable broken at the mechanical part or is it broken before that?
Remove the grill