Well it could be one of two things. One your fuel pump went out or two
(which happened to me but not sure how ) your computer got unpluged. What
i mean about the second one is under your dashboard by your feet straight
up is one or two big silver boxes with what looks like one big computer
cable pluging into it. Make sure its connected or unplug then replug it
back in. What happened to me was it would act like normal when i went to
start it(lights on dash go on etc) but no turnover or nothing. had my
mechanic do tell me same thing exactly. After two days came to find out
that the computer cable kinda came unpluged which caused our fuel pump to
not get any electricity which caused no gas to go where it needed to go.
Go figure.

the mechanic should have been looking at the data stream, that's how you
find out what's wrong. you can buy an OBDII reader for under $75.  More
then likely the culprit is the fuel pump relay, specifically the ground
pin in the 2000. DO NOT use an after market relay as a replacement, use
ONLY a kia relay.there are 2 relays that should be replaced together.
Having changed one recently on my 2000. Also make sure the chassis ground
is clean and making good contact. This car is a rolling computer. Nothing
happens that isn't recorded in the data stream.

you might check http/wwww.automotiveforums/vbulletin/f254  or scrool down
to kia forums. there is a kia with the same problem. the members are
mostly kia mechanics, and helped me out many times on my 2 sportages.