Extremely slow internet connection on Vista.

Hi,

About a week ago i noticed that my internet was running very slowly, prior to this it was fine.

I've got a Studio Hybrid running Vista Home and it's connected via wireless.  I'm now getting speeds of around 4 or 5 kbps.  I know the router is ok as I've also got a laptop which works perfectly.  I've put the Hybrid next to the router so I know it's not a signal issue, I've also connected via ethernet cable and get 4MB download speed so it's just the wireless that's a problem.

I've run full system scans using AVG 9.0 and there were no problems found. I've tried downloading the driver from the Dell website but this made no difference.

I'm new to Vista so don't know what else to try.

Please can anyone help?

Thanks.