Welcome to the forum.
FYI: your machine is NOT a business-oriented Thinkpad, but just another consumer mass-product from Lenovo.
Its keyboard (and other parts) are attached to the motherboard using flat cables without any connectors, that slide into a slot.
It's easy for these cables to come loose or even pop out, which might be your problem.
The cables are held in place by either a slider, or a small lip.
The
slider sits under the whole width of the flat cable and needs to be pulled out on each side of the cable slot VERY carefully, and only for maybe 3-4 mm. Reinsert the cable, make sure it goes in straight and all the way, hold it in place with one hand, and then use the other hand to press the slider gently back in from both sides.
The
lip is gently flipped
up for removal or insertion of the (usually smaller) cable. Reinsert the cable, make sure it goes in straight and all the way, hold it in place with one hand, and then use the other hand to flip the lip gently
down to hold the cable in place.
See here:
http://support.lenovo.com/en_US/detail. ... MIGR-71274
and download the HMM here:
http://support.lenovo.com/en_US/product ... MIGR-70828
Also maybe check this out for fun on Youtube:
http://www.youtube.com/watch?v=Ls5TbcE1GRg