Firstly, if a power supply does anything but simply die a quiet death (and even then), it will usually take something else with it. A PSU with vengeance on its mind can easily be enough to warrant a replacement of the entire machine. If you start noticing hardware failures, it's time to dump it.
On to the problem at hand; make sure you've installed motherboard, video, and sound drivers. With video drivers, make sure that you're using the correct one for your card's era and not simply the newest. As newer cards come out, companies begin "forgetting" to fully support the older models. Remember that if you wish to replace a driver, remove the old one first. It's also good practice to use a driver cleaner after the uninstall to make sure nothing was left behind.
