Getting a new laptop.

I'm also thinking about getting a new computer. Currently i'm using an HP laptop, and its working okay but its starting to slow down (I've had it for 2 years now). I want something that can run MS with almost no lag, but also inexpensive. I've got a pretty decent internet connection, and the only thing that will really slow me is my comp. I'm debating whether to complete wipeout my hard drive and start fresh, or get another computer.