How can I find out which CPUs, graphics cards and sound cards would be compatible with my current motherboard?

Go to the motherboards manufacturer's website. Look up your model and you should see the specs. Graphics cards and sounds cards are nothing to worry about just make sure your motherboard has a slot to support it agp or pciexpress etc. CPU wise just look at the type of mount, not tooo difficult. Make sure you get the memory that is compatible with your computer that's the tricky one the rest is pretty obvious stuff usually listed in the specs of a website.

How can I find out which CPUs, graphics cards and sound cards would be compatible with my current motherboard?
If you now which motherboard you have then you can look for the specs online and it will tell you there was is basically compatible with your computer. It won't say brand but what type such as usb 2.0 or pci-e or agp.
Reply:Find out what brand your motherboard is, and go onto their site. If you don't find anything, try emailing them.