how do i diagnose my connection?

[joyceanblue]

hi guys, i feel that my net is erratic and slow..i dont know whether to blame my downloads, pc, or line. how do i diagnose my connection? im attaching screenshot of my modem page.
http://img20.imageshack.us/img20/6242/screenshottp.jpg

 

[superprash2003]

do you face disconnections? or just slow browsing? or download speed?