The connector on the end is probably an IEC (or 'kettle lead') connector, for good reason - if you check a wired kettle it'll be that same. It's also used on most guitar amps.
Have you added any hardware to the tower recently, either components or RAM? Is there any reason why it should be drawing more power?
Is there a recomended rating on the back of the tower unit, or on top of the PSU? (You might need to look inside your case to see this one.) See
this example - "AC Input" in the top left of the orange box specifies 230V/6A.