The a and z keys specifically doesn't work most of the time. The v key is also showing the tendency to get jammed too. Sometimes its works , without having to do anything or with enough pressure. I'm using the laptop's On-screen keyboard to type in the a , z and v. Why is this happening and can someone please help me out of my misery?
They are not designed to be fixed, unfortunately. Often tiny bits of plastic break off that hold the key in place - even then the missing "key" might still work by tapping the rubber thing underneath. When that fails its time to visit ebay for a replacement.
Key mechanisms need to be dry with no oily substance and certainly no sticky stuff. Clean the keyboard. Especially clean beneath the keys that are sticking. If there are no broken pieces of plastic you should be able to make them work.
After cleaning, tap the keys over and over until they unstick.
If when pulling the key off, if you see a coiled spring, stretch the spring slightly, just a little bit, then replace the key. That usually does the trick. Do not stretch the spring very much.
Pull the keys off and clean the mechanism and plastic underneath with a q-tip and alcohol.
One more thought to add - depending on the particulars of the situation, canned (compressed) air can be used to blow out obstructions (food, hair, dust, whatever). If the problem was caused by a now-dried spill of some sort, you can usually clean it out by using a q-tip moistened with a small amount of 70% rubbing alcohol.