TROUBLE WITH INTERNET SPEED

On my home computer I have Time Warner Cable modem. For the past 6-8
months it has been slow as hell - a dialup connection would be faster.

The weird thing is when I use my laptop with my wireless router it is
not so slow - no bad at all.

I called Time Warner & spent time on tech support & after numerous
tests they said everything shows fine.

I installed new virus software & cleaned up the PC & still no better.

Anyone have any ideas?

Should I just replace the PC? It is a Pentium 4 maybe 2 years old.
.