For my 1998 lexus ls 400. i attempted to jump

You should be able to access 3rd brake light through trunk.

Call the Dealer you purchased the car from, and have them walk you through it. Act as if you are stuck in the middle of nowhere.

Your alarm is keep your system from starting. When the alarm system fails, you have 1 of two choices, if it is a after market alarm then just disconnect the alarm, if it is a manufacture alarm then you will need to take it to a company to have then replace the alarm or disconnect it. Doing so yourself you can hurt your vehicle more then help it

Okay you may want to check to see if the sensor on door lock cylinder hasn't fallen off from the lock itself. Pull of the door panels and check the wires at the door lock cylinder. Hope this helps.

check under the hood for more fuses.

Your keys are prob. worn. My car did the same thing until i got very expensive new keys made.

I went back and tried again and got it done.  Thanks.

under the steering column on the left there is a fuse box there are three metal fuses larger than the normal fuse...there is a tiny hole it is the reset button for the theft detection...check the manual...should be around page 194 i think...you just stick a pin into the hole and should reset.you migt need the alarm code to release the lock on te engine.depends on what type of alarm it has installed...

charge or replace the car battery as low volts can cause this type of fault
to move re place the battery leads turn on dash lights put foot on brake and put in in neutral as there is a elec lock on the gear stick opperated by brake padel

If the car ran and got you home after a jump start I doubt the alternator is bad. Check your battery. And remember never ever disconnect the battery cable with the engine running.