I misplaced my laptop power cord. I have the adapter, it is a 200w one, but the power cord is missing. The connector on the adapter is a IEC 320 C13/C14, the same one on desktop power supply and monitors. My question is, can I use one of those cords instead? Will it be fine since I'm using the right adapter? Will something blow up? Any response would be appreciated.
As long as you're not using a ridiculously cheap, poorly spec'd cable with too small a gauge from the power draw, you'll be fine.
200W from 120V AC is less than 2A, it would be fine even on #24 wires.
AFAIK though, the minimum wire gauge for unprotected AC power cords is #18 as the cords have to have thick enough conductors to safely trip 15A breakers under most typical short-circuit and overload conditions.