Ok There are Lotta Factors For Ur Slow Connection Namely The Amount Of Shared Bandwidth,No Of Users Browsing and Downloadin,Possible Virus Attack And Quite some other factors too.....The Same Net connection and Isp Does not Mean Same Distribution of The Speeds To All Subscribers Mate
Btw Port Blocking Is Usually Done To restrict Certain downloads and Reduce Traffic And Even Virus and Hacking Attacks......Its Just a Safeguard Measure

Use Port detective to Find Out Which Ports Are Blocked Or Not
http://www.portdetective.com/
Why Dont U try Contacting Ur ISp And Inquire About The Diff Between Ur Connection and Ur Friends Speed