Both laptop keyboard and virtual keyboard will not type certain letters

My son has a Dell Inspiron running Windows Vista. His computer was fine and he made no changes to it whatsoever. He came to me very upset claiming that his keyboard was not working properly.
I took a look at it and sure enough, it will not type the following letters:c,h,l,t, ***U,v. Since his password contained the letter "L," once he logged out he was no longer able to log back in.
He asked me to reinstall his operating system. I have done so, except now I'm on the screen where it asks me to type a username and password - and guess what? It still won't type those letters! I even tried the virtual keyboard - it will not type those letters using it either. However, when you press the "U" key (whether on the keyboard or the virutal keyboard) a window pops up titled: Ease of Access, and it gives me the option of hearing text onscreen, making items larger, etc.
I cannot even begin to imagine how to fix this. Please, if any of you know what to do, help me please??

 

OMG! I have to add this additional information:
I just accidentally pressed the "shift" key when I tried to type an "L." It typed the "L!!" But it still will not type a lower case "L." When I press the "Caps Lock" key, it has no effect - it still will not type the letter L. This is the case with all of the above noted letters. All of them will type only if I press the "shift" key.

 

It will not type any numbers no matter what I do, however, when I press the "shift" key and attempt to hit those same keys, it will type the exclamation point, "at" symbol, etc.

 

It does read like it's a keyboard problem, can you borrow a known good keyboard from a friend or neighbour to test?

Only disconnect or connect a keyboard with the computer turned off, you don't want to trigger further problems

 

I am unable to connect the laptop to the internet. Since the laptop will not type numbers I thought I was being smart when I popped my zip drive into my Ubuntu machine and typed a text file with the security code for the network. I saved it and placed the zip drive into the laptop and then copied and pasted the security code into the empty field. When I clicked "connect" I received the following error message "The network security key is not valid. The network key you entered is not valid. Type the key again using 5 or 13 characters; or 10 to 26 characters using digits - 0 9 and letters A - F."

I tried to find a keyboard that will connect to the laptop. The laptop has only USB ports and I have only ps/2 keyboards.