Not Digitally signed?

I'm looking at my DirectX Diagnostic tool and it says for a few things
"The file ati2dvag.dll is not digitally signed" under Video, and "The file RtkHDAud.sys is not digitally signed" under sound 1 and 2. is this a serious problem? it might help solve why I've had a few crashes when playing games maybe? If anyone can help I will be very grateful, especially by telling me how to get these "signed"

My stats are
XP Home Edition (5.1 Build 2600)
1390 RAM 3.33 GHz
Radeon Xpress 200 series

 

I know very little about this kind of stuff but I think it just means it's a driver that hasn't been registered with Microsoft, or something along those lines. I don't believe it affects the operation of the thing.