[Darksun]

Check your fans. If any are not running or running noisy, replace them. Blow out all the dust. If you blew out a lot of dust, the computer may actually run cooler with the case back on.

External drives are great for backup, but not the best thing for running games actively off of.

If your drive is pretty new, it's probably going to last longer than anything else in the case.

It's still a good idea to make multiple backups of everything you care about. Skydrive and foldershare are good options for for distrubuting your backups. I also like the USB drive since it's fast to move from PC to PC. Skydrive can take a few hours to re-replicate all your files.

How warm is "A little warm?" Computer chips can run at 130 deg. F without much problem. If you have a remote thermometer, (the kind with the laser or LED dot for targeting) check out the main chip on the card after you run the game for an hour. If that's 140+ it's probably running too hot. Memory chips can be sensitive to case heat buildup. If the case get up around 120+ inside they sometimes start throwing errors.

If you have specific questions about external drives, I will do my best to answer. I can't tell you doodly squat about multi-player. My internet connection uses carrier pigeons for part of the link, so latency is a problem.