intermittant faulty keyboard and occassional beep

[rogerok]

Hi,I am desperate for accomplished techie help.I bought a Toshiba Satellite L40 laptop last November,so it is in fact still under warrantee.The problem is that when I use the keyboard
for any reason ad am say typing an e-mail for instance,it will leave out the odd character,
but i no specific way,they just don't appear.This means I have to go back over everything as I am typingI have a tecra 9100 which has no such inclinations and can type perfectly ell on.As you can see I am not correcting this as I am going as I usually do so you may see a typical example.
Also what appears to be happening is tht every day or two,while inuse there will come a load single "beep" from the systems board.I have discussed this with the techies at Toshiba
and they have had the laptop back to run diagnostic tests.I noticed there was a bios update due so suggested to them that this could be the solution to the problem.Thisthey did while it was away.They sent the machine back with the message they cold find nothing wrong when
testing with diagnosic equipment.
I know I ha'nt suddenly become word blind as I can type fultlessly on my tecra 9100,all my family get the same results when using the keyboard.Has anyone come across this problem
before?Is it a pculiarity of this particulr laptop or is there an underlying cause?Maybe the two
prblems are inked?I just don't know.I would be very gratful for any ideas,probably just for my curiosity,because the cursed machine is going bck again anyway.