Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
I don't think you need to unplug anything. When you get your new speakers just plug them in. From system preference you can pick which device you would the sound to playback on. In this case, just choose to play back from your mac pro sound output.
I think max out the RAM and putting in an SSD will serve you better. From my experience, running mulitple OS's eats up not just the CPU cycles but also the RAM available.
But I'm not sure how many GB of RAM is capable on your laptop. Adding the SSD is also a good idea because it eats less...
You can go ahead and store other stuff on your external hard drive. Time Machine only works in a dedicated folder on that drive. As long as you don't place any foreign file into the time machine folder you'll be ok.
This happened to me before. and it was Perian that caused the issue, I had to manually remove all the codecs and then reinstall. All is well after that. :p
And for the file that was chopped up into bits and pieces, are you talking about the raw footage that iMovie works with? I don't think there's a way to piece them together, unless you convert the entire video in iMovie to a format that your HTPC can play.
I had a similar incident once when I was helping out my fiance on one of her client's website.
imovie only takes either raw files or mp4 (correct me if I'm wrong) and at the time the only software I have on the computer was VLC, Quicktime Pro and iMovie. And I was too lazy to look for any...