Lagging runescape on a gaming like computer?

[PrincessBella]

So heres the thing,

Runescape is lagging on my computer and its only a year and a bit old and to be honest runescape shouldnt be laggin on a computer with the specs it has...

Specs: (I'm guessing you guys know what this stuff means coz clearly I don't.. )
Intel Core i7-860 2.8GHz 4MB Cache
8GB DDR3 1333MHz Memory
1.5TB SATA 3GB/s Hard Disk Drive NCQ
Blu-Ray Writer
nVidia Geforce N220GT-1GB PCI-E Graphics
19 in 1 Media Card Reader
Tv Tuner Card
Windows 7 - 64 BIT Edition
Modem is brand new and my PC is plugged straight into it via an ethernet cord that is a few years old i must say.

I have run virus scans and there is nothing that comes up Ive done a disk frag, disk clean up and a restore. Atm, im using 0.8% CPU and 40% RAM and that with 4 tabs open in total, I normally have 12 tabs and it works fine when runescape isnt up. How can i see whats using all my RAM and why is it lagging? Please Please Please someone smart help me Oh and what is a tv tuner card? and how do i make it work if it does something

Cheers

 

[Tmagic650]

You may have some programs running in the background when you play runescape. What antivirus program are you running? A TV tuner card is a device that allows you to view live TV on your computer. There is a cable TV connector on the back of your computer. You have to connect a TV cable or antenna to this connector to be able to use the TV card

 

[PrincessBella]

Um, I think its called avast :S Thats what I got told to use. And how do I check for programs running in the background? Oh and thanks for the Tv info too!

 

[Tmagic650]

Remove Avast and download and install Microsoft Security Essentials. See if the lagging stops

 

[PrincessBella]

Okay thank you!