About a month ago all my download stopped by themselves,i.e. the speed dropped to zero.I waited for almost two weeks but nothing happened.
I noticed that all the trackers timed out and didn't connect.This happened for all the torrents I was downloading and tried to download afterwards.I don't know much about all the technical stuff.So I can't tell much about the real technical details about the settings I have.
Can anyone please advice on how to fix this?

You can still browse web/download direct link/ without problem? If so, then maybe your network has some problems or your ISP just started to prevent you from leeching/seeding torrent and other P2P programs.

Without more details, nobody would really can provide any more useful suggestions...

Same thing happened to me. I just got time Warner cable last month and i was downloading. About two weeks ago my download speeds slowed and a week ago my downloads stopped. I am able to surf the web, my phone is able to connect to the wifi. I have a 1 yr old computer but an older linksys router. could you give me an idea of what other info you would need to help me solve this problem?
-NM

Use another Bittorrent client to check to see if it is your ISP or Tixaxi that is causing the problem.

I'm having a similar problem. My torrents can't connect to trackers (some private trackers do work though), so if DHT can't find any peer it won't download. I tried to download the same torrents with another client and I didn't have any problem connecting to trackers.

Use this link to determine if your ISP is blocking your torrent traffic:

http://broadband.mpi-sws.org/transparency/bttest.php

Just choose the bit torrent option at the bottom and hit start testing.  It will tell you the results, which if you do not understand, you can post here for us to interpret.  It is pretty straight forward though.

No problems apparently:

Is your upload traffic rate limited?

There is no indication that your ISP rate limits your uploads.
Is your download traffic rate limited?

There is no indication that your ISP rate limits your downloads.