1st if you use router or modem for your dsl connection try to unplug the power cord or switch off totally. then if you are in dynamic IP surely it will give you a new IP so you can get the faster connection from your ISP. 2nd try to delete cookies, temporary internet files, data forms, etc., from the properties of IE or Mozilla, 3rd if you got the softer cleaner like CCleaner or SuperCleaner those softwares will clean garbage or remove uneccessary file then follow up by cleaning it by Ad-Aware SE personal or Ad-Aware SE Manual. those are the possible solution for DSL problem.
Lastly if you notice you still got the sloppy connection, try to tweak your connection by other possible solution likt.. "full speed" try to search it. i dont know if it is allowed to post the site here, just incase you want to know just site pm me so i wont get warning from here . IF those above mentioned still not be useful for you then i suggest contact your ISP then reformat you PC. and try to put some Internet Security that is not a free version.
Hope this will help you