Windows 7: New build, fresh install of Win7 home prem. Issues

Ok, so I built a new PC lastnight and proceeded to install what I thought to be Windows 7 Home Premium 64bit. After the installation was done, I checked system properties and it's showing as a 32bit OS.

Here are my system specs:
AMD Phenom II x6 1055T Thuban 2.8Ghz Processor
4Gb of G.Skill Ripjaws DDR3 1600 Ram
Gigabyte GA-890GPA-UD3H AM3 AMD 890GX Mobo
Onboard Video ATI Radeon HD 4290
Antec Earthwatts 650w continuous PSU (Crossfire ready)
Onboard Audio Realtec ALC892

When I try and check my Windows Score it says it can't rate my machine due to missing proper multi-media devices.

Basically, what i am asking is:
1) How can I tell that the disk I used was infact 64bit
2) Can my onboard video chipset cause it to not install as 64bit.
3) Did I simply get swindled and was i given a 32bit version instead?
4) Should the install disk prompt me for 64 or 32 bit installs?
I am completely lost with this, as I definitely want the 64bit version and would gladly pay for the upgrade from Home premium to Ultimate 64bit if that's the case, or buy a new copy.

I bought the disk from an ex Dell employee and it's legit (key wise), and labeled as 64bit, but is not offering me any options to choose 64bit installation. Only installing as 32bit.

Any help would be great! Thanks in advance.

Simply go to Control Panel > System, the screen there tells you what you need to know as far as the OS is concerned.

At work right now, will update with a reply as soon as I get home.
I may actually head there for lunch break. Thanks for the quick reply.

First the important things. Type version in search and lets verify the version and edition of Windows 7 that you are using.

It definitely says 32bit OS.

Wow a triple header 3 posts at the same time.

After typing 'version' in the start box, click on "show which operating system your computer is using".

What did it say on the DVD? Did you get two? If so one is 32 the other is 64. I think this is where the error may have occured.

hi MrBentley, was it an OEM disc ? , have you contacted the former employee ?

A legit 64 bit DVD will install as such. You will not be offered a choice during the install.