Ok, now we're getting somewhere. Let me see if I understand your problem correctly. Your computer was built and in good working order, but as a result of you resetting the BIOS, your graphics display isn't as it used to be. But what about the speed of your computer? I associate speed with processing. Are there other apps that run slower than before?
You mentioned locked cores again. Are you sure of the model name of your CPU is Phenom II 9050t? I can't find that one. However, I did find a Phenom X4 9950, which is a quad core CPU. Here's the deal on "locked" cores. A few years ago, there wasn't a very high demand for quad core, but they were manufactured. Some of the Phenoms resulted with defects, and some were made the way they were intended. The Phenoms that had defective cores had said defective cores disabled. In an effort to make a sale on the defective CPUs, AMD marketed these as dual core Athlons.
To make the long story short, the supply vs demand wasn't favoring quad core CPUs, so AMD disable two cores in their Phenoms to meet the demand for dual core CPUs. When this info became publicly known, a lot of people wanted to buy Athlon BEs, with the impression of "unlocking" two cores.
So... Your Phenom, if it is in fact a 9950, is a genuine quad core CPU - no cores to unlock. However, since the 9950 is a BE, or Black Edition, it has an "unlocked" multiplier. Here's how it works...
The Bus of the 9950 is 200 MHz, and the stock multiplier is 13. 13 x 200 MHz = 2600 MHz (2.6 GHz). An unlocked multiplier allows the stock multiplier to be increased when overclocking. This feature is not availble to non-BE CPUs. Keep in mind, that overclocking isn't simply increasing your multiplier; you have to adjust your RAM specs, too.
Speaking of BE and unlocked multipliers, the same principal is applied to your GPU. My assumption here is that the person who built your computer had it overclocked all the way down to the GPU. Was this system built for you by Cyber Power, or a similar company?