That's 114.8F If it's an AMD at idle then you're ok but it's still a liitle warm. If that's an Intel, that too warm for idle. Check the fans and vents to make sure you have plenty of air moving thru the case. Lastly get a can of air from a local shop and blow out the heatsink fins on the cpu. While you're in there blow out the rest of the computer. DO NOT turn the can upside down as the propellent is super cold and can crack a chip.
Just be carefull inside the case.
Static discharge can and will kill a computer as sure as you took a hammer to the motherboard...
As for 24/7 operation, mine is on unless there is a nasty storm. Then it's off and unplug every thing. If you plan to joint the 24/7 crowd I would reccomend a BackUp power supply. A UPS. You don't need a fancy one, just one to give you time to shut down in case you lose power. Belkin makes one, a 350watt model that's smart. Goes for around $38.00USD.