40 - 50 C is about right.
Your PSU should not be too hot to touch - AMD's soak up a lot of power and as you are also running 2 hard drives and I assume CD/DVD players I think that you may be over cooking the PSU.
Try getting a 350 or 400 watt PSU with twin built - in fans. This will help the case to keep cool.
I have had problems with cheap - no name 300 watt PSU's not having the power to drive overclocked 1400 AMD's in the past.
Try
www.overclockers.co.uk for good quality PSU's, Fans . etc.