Automatic PC Self Diagnostics

A few weeks ago my laptop started running extremely slowly, and I began bracing myself for the worst.  I ran a virus check, and made sure my affairs backups were in order.  I thought this was the end for my almost 4 year old laptop, until I noticed that my computer was unusually quiet.  I next noticed that my CPU was running really hot (I have this handy app that displays my CPU temperature in my system tray).  Sure enough the fan wasn't spinning.  A few minutes with a compressed air canister and I had successfully blown out the dust that was gumming it up.  Disaster averted.  And probably just in time too, had I continued to run my computer without the fan it could have been permanently damaged.  While I'm really relieved the problem was so minor, I'm also a little annoyed that my computer (or any computer that I know of) doesn't notify the user if things at the hardware level are running sub-optimally or not at all.  Most new computers provide ways to run tests on almost every part of the system (including the fan), yet to run them it often involves booting the computer into some archaic looking "diagnostic" mode.  But really the operating system should periodically run hardware level tests and notify the user if something fails or is preforming way worse than it should.  In fact it doesn't even have to notify the user, there just needs to be a quick way for the user to check the results of the test when something seems off.