How many other programs are running when you try to play them? I know if I'm doing a lot of d/ling while trying to view a video, it will act like that. Try cutting down on the number of d/ls you have going, also if you have a lot of uploads going it will slow your computer.
You can adjust the amount of bandwidth you allow for limewire by going to Tools>Options>Downloads, to set your d/l bandwidth, and Tools>Options>Uploads>Basic to set the upload bandwidth. You should set it to about 80% of your max. Do a couple speedtests to see what speeds you have to work with.
Here's a couple speedtest sites:
http://www.speakeasy.net/speedtest/ http://www.dslreports.com/stest http://specials.zdnet.co.uk/misc/ban...eedtest50.html
This link has tips for setting up LW:
A few things to consider while configuring Limewire for optimal performance...