how do i go about checking that my psu is strong enough for my computer
First you need to have a look at the label on the side of the psu for it's wattage and 12 volt amperage, then you need to go to - http://www.extreme.outervision.com/psucalculator.jsp to see how much power your pc is actually using.
thanks for the help
If you need any more help or advice don't hesitate to ask.
after using a PSU calculator, add 30% for cushion.