Can anyone tell me why my computer smells bad?

Just recently my old hard drive began to click and whine and I replaced it with a brand new one - A Seagate with 160 gb. However, since I've installed the new one my computer gives off a really weird smell when the computer is running. I can only describe it as an ozone type of smell which, after breathing in the fumes, makes my throat hurt when I swallow. I should mention also that my hard drive is running perfectly fine, I've opened the case while my computer is on and none of the internal parts are overheating - just that awful smell! The same thing happened recently when I installed a new video card. I had to stop using it and buy a used one. Am I over sensitive, or does all new computer equiptment smell this bad?