I have got a dell laptop that's got windows Vista on. I want to fit a new hard drive and load windows 7 on it.  I have done this with desktops before, is it straight forward with laptops? 

No difference.   Laptops and desktops are basically the same except for their outer shell.

As Pib has said, very similar. Might be an idea to go to the laptop manufacturer's website and download the drivers for 7 before doing the install.

I've got an older DELL 1440 with W 10 Pro on it and you can easily do that alone.

 

               Got to an Advice shop in your area, they're cheap and you'll have a warranty. 

 

    Only two screws and you can take out the HD. Please be careful when you insert the new one, especially when it's a flat one to make sure that it really fits and is connected.