Explanation:
Interesting problem that can happen to coffee drinkers and slush lovers.
Most of the time, multiple sticking keys simultaneously appearing infer a recent (3 days to a week) spill of a sugary liquid on the keyboard.
If it is a built in laptop keyboard, read no further, confide in a repair shop because keys are not easy to open, and harder to put back.
If it is a USB (or PS2) keyboard, AND you are handy, AND you can lift the key tops (and put them back), you can detach keyboard from computer, then after removing key tops of the sticky keys, try cleaning with warm (to better disolve the sugar) water with a non-dripping cotton tip and dry with cotton swaps. Let dry for the next few days before plugging in again. Do NOT use solvents, and definitely NOT "contact cleaners".
The safest and suggested option is to replace the (detachable) keyboard with a compatible or similar one. If PS2 keyboards are hard to find, there are converter cables that plug into the PS2 sockets of the computer, and accept USB input (and reverse cables).