First, sorry if this is in the wrong section, but I couldn't find any sub-forum to do with building computers so I thought I'd put it here. And this is my first post so hello everyone 
I've been using a computer for a good while now, probably for the best of about 7 years and I can fix things onscreen quite well, but I've never bothered to see whats inside my machine or find out how it all works. The most I've ever done with it is take the case off and clean it.
I'm also a gamer but with my current computer, I have to run all the settings on the lowest even in WoW to ensure I just get 30fps... and thats with no one around. My graphics card is a Radeon HD 2400 and I'm using an intel pentium dual core E2160 @ 1.8 ghz with 1 GB of RAM and even I know thats not brilliant so I've decided to list up some parts... problem being I don't know if they're compatible with eachother and I haven't really done this before so this is where I need help. I'm also on a budget of no more than £450.
CPU - AMD Phenom II x4 955 3.2GHz
RAM - CORSAIR 4GB 1333MHz CL9 DDR3 (Comes bundled with CPU for £166.89)
MOTHERBOARD - ASUS M4A77T ATX AMD 770 SOCKET AM3 (£58.37)
GPU - Sapphire Radeon HD5770 (£97.99)
CD DRIVE - Liteon IHAP122-19 22x Internal DVDRW (£15.99)
PSU - 750w
CASE - Zalman Z7-PLUS Mid-Tower ATX Gaming Computer Chassis
HARD DRIVE - Seagate OEM 500GB Barracuda 3.5 inch 7200.12 Internal Hard Disk Drive (7200RPM, SATA, 16MB Cache) (Case, PSU, and HARD DRIVE comes bundled for £106.42)
The CPU comes with a heatsink/fan and thermal paste already applied. Any help would be greatly appreciated.

I've been using a computer for a good while now, probably for the best of about 7 years and I can fix things onscreen quite well, but I've never bothered to see whats inside my machine or find out how it all works. The most I've ever done with it is take the case off and clean it.
I'm also a gamer but with my current computer, I have to run all the settings on the lowest even in WoW to ensure I just get 30fps... and thats with no one around. My graphics card is a Radeon HD 2400 and I'm using an intel pentium dual core E2160 @ 1.8 ghz with 1 GB of RAM and even I know thats not brilliant so I've decided to list up some parts... problem being I don't know if they're compatible with eachother and I haven't really done this before so this is where I need help. I'm also on a budget of no more than £450.
CPU - AMD Phenom II x4 955 3.2GHz
RAM - CORSAIR 4GB 1333MHz CL9 DDR3 (Comes bundled with CPU for £166.89)
MOTHERBOARD - ASUS M4A77T ATX AMD 770 SOCKET AM3 (£58.37)
GPU - Sapphire Radeon HD5770 (£97.99)
CD DRIVE - Liteon IHAP122-19 22x Internal DVDRW (£15.99)
PSU - 750w
CASE - Zalman Z7-PLUS Mid-Tower ATX Gaming Computer Chassis
HARD DRIVE - Seagate OEM 500GB Barracuda 3.5 inch 7200.12 Internal Hard Disk Drive (7200RPM, SATA, 16MB Cache) (Case, PSU, and HARD DRIVE comes bundled for £106.42)
The CPU comes with a heatsink/fan and thermal paste already applied. Any help would be greatly appreciated.