What type of connection do you have? If it's dial-up you better tell us.

Try deleting your LW Preferences folder whilst LW is closed; instructions here: Fixes for Limewire

Make sure you know your connection speed. See here: http://www.broadbandreports.com/tools OR http://www.t1shopper.com/tools/speedtest/ if you're not sure.

Try:
1. Set your speed appropriately (Tools>Options>Speed) & select which one applies to you. Tick Disable Ultrapeer Cap. & press Apply.
In LimeWire the speeds assigned as follows:

Modem/ISDN = 56 to 128 kbit/s (7-16 KB/s)
Cable/DSL = 350 to 999 kbit/s (44-125 KB/s)
T1 = 1 Mbit/s to 2.9 Mbit/s (125-360 KB/s)
T3 = 3 Mbit/s or more (350 KB/s up)

2. Reduce your uploads to 50-80% of your known & tested Upld speed (Tools>Options>Upld>Basic) & also set uplds for Autoclear & press Apply.

3. Reduce downlds to 75-90% of known & tested Downld speed (Tools>Options>Downlds) & also set dwnlds for Autoclear & press Apply.

4. Disable LW's media player (Tools>Options>Player) & untick & press Apply button.

5. (a) After opening LW let it settle for 10-20 mins before using. (b) Do not use the Resume/Find Sources on all your files to continue them (this has side-fx) (c) Don't select too many files to downld at one time.