When I press certain letters to text qwerty and random chains of letters appear

I was wondering what keyboard you are using then. Is it for laptop or for desktop?
Let us assume that it is for desktop. Try to have patience to do the following.
option 1.
1. turn off you pc.
2. if your keyboard is connected as usb, gently disconnect it.
3. if you have a blower, try cleaning the keyboard by using the blower, if you have none, this will be remedied by an empty bottle of rubbing alcohol. squeezing it, will blow those dirt on your keyboard. turn your keyboard upside down to let those dirt fall off.
4. use a brush to clean those dirt.
5. before connecting it back to your pc, have a last inspection, verify that all keys are free and smooth to press, that there are no more dirt stuck underneath them.
6. connect it again to your pc and turn your system on and verify if it is working well.

option 2.
1. borrow another keyboard and replace yours and check if that works. once the borrowed keyboard is working, then you already know that your own keyboard has the faults. try to do option 1. otherwise, replace the faulty keyboard with a new one ;-)

option 3.
1. while your system is on, and your keyboard connected, if it is usb connection, simply, disconnect and connect your keyboard on the same port. if it is still not working well, use another usb port and connect it from there and test it again.
2. if your keyboard has a cd installer comes with it, installing it would also help as that will install the needed driver for your keyboard, if a cd doesn't comes with it. just try to do the step 1 in option 3. ;-)

please note, that if you are using a laptop, then the keyboard i suppose is very much installed and very hard to remove and replace without disassembling the whole unit, then the only option on that is a separate keyboard hardware connected to a usb port. if the usb connected keyboard works, then it is time for you to send it to technician for further check up, they will need to disassemble it check the keyboard's pcb, and if they need to clean it, they will do it, let us not hope for the worst, that they have to replace the whole keyboard, that takes time, depending on the availability of the hardware.

hope this helps. and don't worry, you will do just fine.

@muchlovekiki

Try to do the following:

1. Boot your computer in Safe Mode (press F8 simultaneously after you turn the computer ON) and check if the keyboard still displays random characters when you type qwerty.
2. If it works fine, check this guide on how to disable startup items that might be causing the problem.
3. If same problem occurs, try to use an external USB keyboard and check if the issue persists.

If using an external keyboard fixes the problem, that is a sign that your laptop keyboard is already wearing out and needs replacement.

Good luck.