The keyboard malfunction seems typical for water (or other liquid) damage: the liquid has entered the keyboard wiring matrix and is causing short circuits in it.
If the DVD drive has also started to fail at the same time, it's possible that both faults have the same root cause. Water intrusion is unfortunately a rather common reason for laptop failures.
The "Safety and General Information Guide" for Lenovo laptops has instructions for cleaning the computer in Chapter 2:
Cleaning the cover of your computer
Occasionally clean your computer as follows:
1 Prepare a mixture of a gentle kitchen-use detergent (one that does not
contain abrasive powder or strong chemicals such as acid or alkaline).
Use 5 parts water to 1 part detergent.
2 Absorb the diluted detergent into a sponge.
3 Squeeze excess liquid from the sponge.
4 Wipe the cover with the sponge, using a circular motion and taking care not to let any excess liquid drip.
5 Wipe the surface to remove the detergent.
6 Rinse the sponge with clean running water.
7 Wipe the cover with the clean sponge.
8 Wipe the surface again with a dry, soft lint-free cloth.
9 Wait for the surface to dry completely and remove any cloth fibers from the computer surface.
Note: Shut down the computer and then disconnect the power cord before
cleaning the computer.
Cleaning your computer keyboard
1 Absorb some isopropyl rubbing alcohol on a soft, dust-free cloth.
2 Wipe each keytop surface with the cloth. Wipe the keys one by one; if you wipe several keys at a time, the cloth may hook onto an adjacent key and possibly damage it. Make sure that no liquid drips onto or between the
3 Allow to dry.
4 To remove any crumbs and dust from beneath the keys, you can use a
camera blower with a brush or cool air from a hair drier.
Note: Avoid spraying cleaner directly on the display or the keyboard.