Replace car computer with home computer?

Aaron is completely correct in his statement... and then some.

When the mechanic told you that "your car computer broke" he is NOT referring to a computer like the ones we use sitting at a desktop or laptop. If you looked under your hood, you would not find a hard drive and all the other parts you would associate with a typical home computer. The computer in your car is most likely of a single chip design where all of the I/O interfaces and software are pressed right onto a single microprocessor. You're not going to find a copy of Windows, Mac OS X or Linux running there!

You'd also find that there are all kinds of custom, proprietary connections necessary for all the different systems inside your vehicle. No typical PC is going to have those, either.

The most damaging part is the conditions you'd find under the hood of your car. The engine compartment is not sealed and weather tight! All the rain, sleet, snow and road grease and grime would quickly overwealm and destroy any normal computer you'd try to put in there. You're just not dealing with conditions a standard PC is meant to take!

I think the confusion arises because when someone uses the term "computer" that most people think of the standard desktop or laptop unit we use on a daily basis. But the term "computer" is a generic term and actually refers to any device capable of performing calculations and following instructions. A pocket calculator is a simple form of a computer... as are the control chips found in devices like microwave ovens, DVD players, televisions and most other consumer electronic devices. You couldn't replace their control chips with your home PC... but they do have "computer chips" that allow them to perform their normal functions.

Yes it will. A home computer has 10 times the computing power as even the most complex car computer. Just get an inverter and plug the computer into it.

I doubt it, car computers are designed differently and use completely different operating systems.

Yes, you can install a Windows PC in your car.

But then your car will crash at least once a week.

Do you really want your car running Windows?