Is my PSU unable to cope with the demand?

[LeonE]

I've been running the following for a while:

Elitegroup Computers 741GX-M Motherboard
AMD Athlon XP 2600+ Processor (2 GHz)
Leadtek Winfast A400GT 256Mb AGP Graphics Card
1.5 Gb DDR RAM
Hitachi 40 Gb 7200 RPM Hard Drive
AOpen 16x CD/DVD Dual Layer ReWriter
Etech 400W PSU
2 x Silenx case fans

Yesterday I added a 2nd HD (80 Gb Samsung Spinpoint) and noticed that now one of my case fans doesn't work. Is it feasible that my PSU can't cope with what I'm asking of it and has therefore shut down one of the fans?
Maybe before posting I should have tried disconnecting the remaining fan and plugging the other one back in to see if that made it work, but I didn't think of that until now!

 

[SNGX1275]

Unplug the hard drive, see if the fan works. Fans use very little power so I'm suprised it would quit spinning.

 

[Tedster]

Your PSU should be sufficient. However if it is old, subtract 30% from stated wattage.