Windows 7: Internet connection

HI just want to ask about internet speeds.as of late my speed goes up and down ,when i run a speed test my download speed goes from 25.30m down to 3.9 and thin back up to 25.30 and upload stays at 6m I had comcast come out and replace the cableand its still the same . is thire something in the comp I could check could the comp cause the problem?

Hi.

Need some more info.
Do this:
visit http://www.pingplotter.com/downloads/pngplt_std.exe -> install pingplotter and made a test against for example. google.com. Choose sampling "Unlimited", trace interval "1 second" and samples to include "ALL". Take a screenshot and post it.

This will show if you have any leaks.
If you have a router or something like it, remove it and just shove the cable into your comp and try. That will eliminate the option of it being your router/etc.