I have a 98 civic lx with a manual and tonight I was driving and the car just turn off on me while driving at 70km/h in 4th gear. Then tried boosting the battery but every time I tried to start it the engine didn't even turn at all. Some possiblilities I thought of was that the battery is officially dead cause the engine won't turn or another possibilitie is timing belt because it was ready to go. What do you guys think?
By the way the engine didn't go off with any bangs, just turned off.

It sounds like you had what's called an engine seize. Have you tried to turn the motor over by hand ? Either by the ring gear or by turning the fan and seeing if the engine turns. If neither works the engine is frozen. ( seized )

. Check if the timing belt broke.

. Perform tests below:

https://www.askmehelpdesk.com/cars-t...ml#post2123675

If it cranks but won't start, replace the Ignition Control Module and coil:

https://www.askmehelpdesk.com/cars-t...tml#post265896