Hi All I am a newbie to this ere Forum, and i got a problem

I have a Samsung R60 plus Laptop
Running an intel core 2 dup processor and Windows Vista OS
I am on a wireless network(netgear with aol)

I have had the laptop for about 5 Months and up until a couple of days ago i’ve had no apparent internet problems…
Until then.. all of a sudden my laptops performance dropped terrible..
when downloading videos or files, it takes agesit says i have like 27.5kb a min, it says estimated time days.. on a file that would normally take 10 minutes…
The only thing i can think of that may have done something is that i removed the Mcafee Free trial from my computer by downloading the tool and removing it…
I then downloaded Avg 8.0 , ran a virus-scan no threats found, i have now uninstalled that and not running any anti-virus… but that isnt the problem as i have been unprotected for months and it has been fine…
Normal web pages like Google and such like are mmm, ok i suppose its tolerable… but when streaming videos online,. it is just pathetic……….
One thing i will mention that is a bit hard to explain is this…
when my laptop was running fine the signal was usually 2-3 bars…
now when the laptop is running slow, it is 4-5 bars and very good signal, … that i do no understand lol……
i have tried switching the firewall off, and it is still slow…
I m not very computer literate and wouldnt trust myself with any mega things… so if you could explain in simple format for me please…
any help on this matter would be appreciated as i want to get it sorted soon lol
so thankyou very much in advance if you can help me
thanks…