Keyboard wont work

[Passmarkcomp]

The letters e, g, i, o, q, t, alt, and enter dont work on my Sony Vaio Laptop. It just happened suddeny. Im pretty sure nothing is stuck underneath the keys. I am using the onscreen keyboard now. Are there any solutions that wont involve me paying? Thanks in advance!

[passmark]

On some keybaords you can lift of the keys to clean under them.
You could also just plug in an external USB keyboard.
You can also probably buy a replacement keyboard and replace it yourself for not too much $$