Just to expand a bit on what dc3
had mentioned, yes, it can damage your system. Most typically, it will do more damage if a system is overloaded, but it could also cause damage if it's not getting enough power. Most power supplies will prevent damage to a computer by either popping a fuse/circuit or just flat out dying (cheaper to replace a single psu then an entire system).
You could get a UPS
(Uninterrupted Power Source) that will regulate the voltage (a ups that conditions also). This will help to regulate the voltage that is going into your computer. Most (if not all) ups's will also act as a surge protector too. When the voltage drops to below 240, the ups will boost it back up to 240 via a battery. If it surges above 240, the ups will cut the power from the outlet, and power your computer via the battery. If power goes out, the ups will continue to power your computer (not really long though, it varies by the psu, but long enough for you to save your work and power down the computer).
Hope this helps!
War produces veterans, wounded both physically and mentally. They have sacrificed for us.....and it is now our job to help these veterans, as they have already helped us in ways we will never know, in ways that we cannot fathom, and in ways that we take granted every day.