Theres alot of things that can cause this.
If as you say you arent "technical" then some of these may not appeal to you.
Run a complete sweep for viruses malware etc etc.
Check your Startup file to see if theres anything there that could be trying to access the internet all the time. Start> Run> msconfig>startup
Do you have enough free space on your Hard Drive, around 10% free ?
Is there any software installed thats trying to access the internet all the time
Ctr +Alt+Del see what processes are running and whats maybe using all the resources.
Does you HD need defragging, Win 7 usually does a decent auto job, but you never know
Back up all your personal files like photos , music etc and re-install Windows
that should keep you busy