Annoying problem...internet or computer???

Hello,

I recently bought a new laptop and within 2 weeks I upgraded it to Windows 7.
Ever since I switched to Windows 7, my internet seems to have become really bad.

Every now and then firefox just refuses to load the pages that I want and I have to restart the laptop for it to start loading pages.

However, recently the internet seems to just take forever to load...it goes onto limited connection often and the download speed is dreadful!! I am currently trying to download the iTunes setup and it says it is going to take 1 hour and 25 minutes to download (15KB/sec)...whilst I'm right next to the wireless router.

The other laptop in my house seems to be working perfectly.

Please help!!
Thanks