1990 Accord Previous Alarm

I purchased my car and the previous owner mentioned that there had been a Honda Factory Security system installed but it didn't work anymore. So today I decided to disconnect the "Brain" and just leave the previous wiring under the driver seat. I am in the process of looking for a car alarm (if lucky keyless entry too) But as I looked under the dash I noticed that there was still all the wires from the past. All of the wires were in a large bulk right by the fuse box. My ignition is still run through the ignition switch (?) because I was going to take out all of the old wiring to prepare for the new alarm. But my main question is, can I still use the old wiring and somehow install it myself?

thats the factory installed alarm (at the honda dealer) Mark the location of the wires and wire up your new alarm to there. Dont use the old wires (unless you mean there is a T harness that that the dealer put in, if so. use it)
And i dont think factory had alarm, just basic keyless entry.

What does the T Harness look like? There is a white box type thing bolted on underneath the dash and it has two connections within it. Would it be hard for me to do keyless entry? and the wiring under the seat would i just tie that into the new wiring? How would I get rid of the old wires since they are all taped and tangled together? And about the factory alarm I think you are right about it being just a keyless entry although there is a led light ontop of the steering column. Thanks for the previous reply.

https://bulldogsecurity.com/MTweb/products.asp?id=1020
thats how T harness look like
1990 accord
thats your diagram. If you do have a T harness, disconnect the wires that goes to there. And the other wires, just untape them and pull the wire from the brain away from the car.
Hope that helps

alright both the links were really helpful and I'm pretty sure I do have a "T Harness" because i recgonize all of the connections. I had a wiring chart already printed off like the one you gave the link to but the one you gave is alot better. But now if I get a new alarm do I keep the "T Harness" and everything? or should I buy a new one? The problem with everything thats confusing me is I cant disconnect anything from underneath there cuz it either runs to the ignition or to the acc. I've started to label all the wires although the old wiring guide was confusing hopefully the new one will help. And also my locks are power but when you lock the doors you have to either push the lock button then pull the door handle or lock from the outside with the key.. is keyless entry even possible with this?

you can use that T Harness, just cut the wire that leads to the alarm (from the harness)
From the harness, you should have your 12V, Starrter, Iginition, Accessory, and other wire that the harness connects together
From your alarm connect your 12v, iginition (starter and Accessory too, if your doing remote start) at the T harness.
Yes keyless entry is possible, i think your testing your lock and unlock with the door open. It has to be close (Accords)
T harness only simplify the connect at the iginition harness, you got to findyour other wires too (door trigger, lock/unlock, etc.)