I believe resolution and color depth are related to the amount of video RAM on the video 'card'. I don't know what size LCD you were looking at either as some smaller LCDs built for older computers like my Digital Hinote could only...
It's one of two things.
1. inverter for the backlight
2. the backlight tube itself (like a really tiny florescent lamp)
Its not uncommon for them to make noise. Unless it fails I don't think Sager will replace it but you can always...
I'd also like to add that the headphone jack is less then ideal for using as input to your stereo. Your stereo isn't really designed to take the voltage level that the headphone jack outputs and will produce distortion and worst case...
An ethernet crossover cable is going to be the quickest.
Set Computer A (new computer) with an
Subnet Mask 255.255.255.0
Computer B (old computer)