Hi, first post here.
I have Limewire 4.8.1, and there has been no problem with Limewire since I started using it 2 months ago.

However, I have not used it for about 2 weeks because of the exam, and now there is a major problem.
Before when I download files with many users, the speed is usually more than 60kb/s, sometimes even peaking to 100+ kb/s. I have cable connection (Shaw cable in Canada).

Now the speed is extremely slow. It takes more time to start. It also takes a long time for connection to become excellent, and it takes a long time for it to start downloading. The speed for some starts at 10kb/s and soon drops to 1kb/s and most of the time stays at 0kb/s. Also, I have to wait in line many times. Other than that, everything else is fine. I can do searches and browse my library. However, I have not monitored any uploads from me.

Another strange thing is that even though Limewire is not supposed to be a memory consuming software, it takes up a lot of memory. The memory usage in Windows Task Manager shows that Limewire is taking up more and more memory as it goes. It increases to a point where it slows down the computer and cause insufficient memory. I have a new laptop with pretty decent specs (512mb and 1.8 Pentium M), so theoretically it shouldn't slow the computer.

One thing happened that could affect Limewire during the time I did not use was that my trial subscription for McAfee expired. There is personal firewall and privacy service on McAfee and now they can't be used. I did not tamper with Windows firewall or Limewire. I use a router at home which is unencrypted (I am too lazy and I'm sure no one is stealing my internet). I did not change any router setting either. I also know it's not the ISP because my friend with the same ISP runs Limewire just fine.

Right now, Limewire is my only downloading program. If someone could help me out, preferably explaining the solution in a way that is not too technical would be greatly appreciated. Thank you for reading this long post.

Shaw cable is known to filter p2p speeds which may be applied to individuals. That might not apply to you.
Your McAffee firewall should probably be removed to be on the safe side if it's no longer functioning normally. Firewall configuration to give LW full access: http://www.limewire.com/english/content/firewalls.shtml
Do this test: Bug Report instructions & sample image If false then you have some type of firewall issue which will either be due to your comp firewall or modem/router.

Sometimes simple fixes can repair things: Try deleting your LW Preferences folder whilst LW is closed; instructions here: Fixes for Limewire

LW can use a lot of ram or cpu depending on how it's used. There's things you can do to reduce it at least. Updating your Java to 1.5 might help. Not resuming all your files using the Resume/Find Sources button will help. Disabling ultrapeer abilities. Setting uplds & downlds for autoclear. After opening LW wait 10 to 20 mins before using. Let it settle down 1st. For more hints you can search the forum.