CRV Keyless unlocking/locking problem

Hi! I just bought a CRV 1998 model from my sister, the Keyless remote sometimes works and sometimes it doesn't especially in the driver's side. Sometimes you could lock all the 3 doors via remote except the door side of the driver, and if it did happen i noticed that the lock tab on the driver side is just partially moved down, when i was trying to lock it again via remote repeatedly it couldn't move down totally, the lock tab was just moving very little, so i ended up locking it manually with a key.
The Panic button is not working totally but the back trunk door works flawlessly. I already tried changing the battery of the keyless remote with a new one, but it still the same. I asked my sister about this, she said she never use it eversince she bought it as a 2nd hand car, becoz she knew its not working and didnt bother to fix it. She just used to lock and unlock the door manually.

What do you think is the problem? Please Help, i really want to fix it.
Thanks.

one of my door locks was sticking like yours. I fixed it by taking off the panel covering the door and shot lot's of lubricant down onto the linkage and manually work the lock mechanism several times . it seems to free mine up so the keyfob will remotely lock and unlock those doors.

Try that and good luck. Otherwise you may need to get a new electric lock solenoid that actuates the linkage.