Johnnycat2525,
It sounds like a codec/driver conflict,you may want to think about getting a codec and Direcshow filter that does not use as much RAM and CPU power like FFdshow,which can be found here>
Free-Codecs.com :: Download latest audio codecs, video codecs, codec packs and tools, FREE!, I recommend the CCCP(Combined Community Codec Pack) and playing your movie files in Windows Media Player Classic.
As with the ideas above,defrag your hard drive,or at least just the files,Limewire allocates space from all over you HDD,so after downloading severl files I use Auslogics Disk Defragmenter(it actually only defrags files,not the entire disk) and no annoying LONG start up delays while it "analyzes" your system. It is available here>
Auslogics - Download Auslogics Registry Defrag.
Also make sure you have the latest updated drivers and windows updates.
You may also want to enter your BIOS on reboot and make sure your RAM and CPU are running at the appropriate clock rating(you may even want to check to see if your BIOS is up to date as well)
My Dad had a similar Problem on a Celeron(CRAP) 1.8 GHZ With On-Board 64MB Shared Memory,He had upgrade his RAM so the clock was to slow,I changed his BIOS settings and Used SIS Sandra to tweak his entire system...it almost runs like a Pentium Class now!!
Hint: If you have files that have already allocated space in Limewire DO NOT DEFRAG YOUR HD,this will cause the resumed file to be CORRUPT!!(do to the aforementioned erratic way limewire allocated space for these files) I really wish they would develop a linear algorythym(if you HDD space allowed it,then if not go to the erratic one))