Hey there, “old lady!” Welcome to MP3Car!
Since you already got some equipment, I take it you want to use that and go forward. The ASUS machine you purchased should get the job done; you just need some extra accessories.
• For the auto diagnostics, your car does use the OBD-I scanner. Check out this unit for starters, and do check out a good Serial-USB converter (yeah, there should be one Amazon recommends on the same page); you will need it to connect the reader to the computer. Software is included with it, but you may find better solutions on the internet.
• Music & movies should not be a problem, as long as you allocate the right amount of space for it. As @Happy_Feet suggested, a front-end software (Centrafuse, for example) would be ideal if you want to run your CarPC like a car. It is not necessary, but it would save you from any unnecessary clicks.
• Does your phone do tethering (internet sharing)? Because you will need some sort of mobile hotspot (or free wifi) to access the internet in your CarPC.
• GPS – I use the earlier version to this model and it works fine. But this adapter is highly recommended. As far as software is concerned, there are options; and @SNOtwistR can give you his recommendation(s).
• As far as connecting it to the car, @DarquePervert’s suggestion of an inverter may be best for your car/computer.
Before I go, there are some questions you might want to consider:
1. What operating system (OS) are you using? The Windows 7 that the computer came with? Because Linux and Windows 8 might be better options.
2. What speakers/audio setup do you have? If you have stock speakers and like it, then that’s cool. If you have stock and it’s getting old, then that’s something else to consider. Or maybe you have upgraded speakers already…
2a. Is your system including amplifiers and subwoofers? Because you have to connect the speakers to your computer, and you might as well make sure it sounds very good.
3. Now that the thread has thrown the tablet-PC idea at you, is that something you want to consider? There are models out there with GPS/Wifi built-in, so there is not much accessories to buy.
4. THE MOST IMPORTANT (to me anyways) –Are you fabricating any part of this CarPC? Are you just mounting the PC and screen in certain parts of the car? Do you want to make it look like the whole thing is part of the car? Will you/Do-you-know-someone-who-will help put this all together? Once you know that for sure, you are on your way.
Best of luck to you!