MBA dead keyboard/trackpad

Has anyone any ideas on why my keyboard and trackpad would all of the sudden stop working? Was working one day, closed the lid, and the next day the only working key is the power button. I can use the bluetooth keyboard/mouse with no problem. Have restarted several times but with no keyboard I can't reset either SMC or PRAM.

Apple said for a flat fee that will fix whatever the problem is. Any chance it could be a trojan or virus of some sort that root'd itself on the boot partition?

Thanks

More details

OK it seems to be intermittent. It started last Monday after closing the lid on Sunday. Then last night it was working again. It went to sleep and waking it up this morning they are gone again. Can this be hardware or software?