No it can't!! Of course, there are exceptions, but rare, and I'm not aware of any such cases. Any faulty electronics can catch on fire, even cell phones, that's why manufacturer's test them extensively, unless of course it's made in China. Basically, in a desktop it's pretty much impossible. Power supplies have transformers in them, and each transformer has a build in fuse, which will burn out and you won't have any power.
In laptops, it's different, because laptops have batteries and external power supplies. If any of those two components are faulty, then there is a danger of heat and fire (surroundings catching on fire). Thinking of buying cheap(er) replacement batteries or power supplies from China?
Now, you also have to think about things into which your stuff is plugged in. Let's say you have a desktop, monitor, external modems, routers, couple of printers, we are talking about 2000+ WATTS, and you plug everything into a power splitter designed for a quarter of that power. That can catch fire. I even had that once happen to me, and I now have a fire extinguisher right next to my desktop. (go ahead touch those wires in the back, are they warm? on some power monster step ups those wires will get hot)
The only sure way to blow up something is to use thermite. Here is Mr don't mess with zohan doing just that.
http://www.youtube.com/watch?v=5EVJFg4dxVA
down side is later on people might find evidence of thermite in the rubble lol
P.S. Almost forgot!!! I once burned out CPU and Motherboard while playing Collin McRae Ralley. I had XP 2000+ and Biostar mobo. No idea how it happened but I had to replace CPU and Mobo. No fire.