If gamins not required why not use the integrated gpu?
The Radeon HD 5450 does not use a lot of power at all. At most it uses 13w of power and that would be when playing games. You should have no problems with a 240w PSU. Playing a Blu-ray movie uses 9w.
Click following for power consumption charts.http://www.techpowerup.com/reviews/HIS/HD_5450_1_GB/27.html
jaguarskx - excellent, thanks.
firo40 - the onboard 3100 isn't working correctly - causing display issues.