The op isn't here they are either in bed at work or enjoying life like we should instead of being up late lol trying to help folks.
external keyboard good ideal my guess would be pull keys off that don't work and clean in that area if that dont help find a local shop to work on your laptop.
warranty ship the laptop off to get in return a refurbished item with someone before you problems yep been there with a Toshiba and after they sent me a new lappy if did the same as before opps they sent my old one back to me saying it was fixed and motherboard replaced guess what the hARD DRIVE WAS GOING BAD BOUGHT A NEW ONE IT WORKED FINE. Sorry new side wider keyboard my best advice flip the latop upside down shake lightly and remove all crap...