Hood won't open on my z3 - 1998 BMW Z3 Roadster

Perform a compression test on your cylinders. One unfortunate result of overheating is the blown head gasket. Without compression your motor will not run. Tester are not super expensive or some stores will lend tools.

Try going underneath the bottom and locating wire to hood, and very gently pull towards you not engine(as it will tear or break. and then your hood should open.

Raise hood,have some one go pull hood latch and you look at latch and see if it releases,if it doesn't then cable may need replacing,I would'nt completely shut hood cause you may not get back open,also check hood latches bolts and latch for something bent or broken.

Go to hood and push down on it and try release lever,if still doesn't open,then go back to hood and release lever at hood and try to raise or push down to lock.

check your ignition system
hope you find it

WHen I have a car with a hood that won't open, I go thru the grille. Disassemble the grille off the front of the car, and anything else in the way until you can get a hand/screwdriver/pry bar/etc. on the
lock release, and reach up and release it. What happens with hood release mechanisms is that they experience rough use (hood open/close cycles combined with road vibration), and become loose. Once they're loose even a little (even as little as a quarter inch), the hood won't open.

if you can get hold of the outer cable at front of hood and pull it hood might pop

Have someone push down on the hood & shake it,
while you try the hood release

If it opens, don't close it until you clean & lube things

The trunk latch is operated by a solenoid which it requires power to operate. since the batery is flat then it won't work. I'm not sure where the positive terminal is under the hood but you can connect the positive lead to the alternator wire terminal, and the negative lead can be connected any where on the engine.
Good luck......

should be around $400