What are your system specs, specifically the CPU type, Physical Memory, and Operating system specs?
You can get this info by going to control panel and setting "veiw by"(upper right side of window) to "Large icons" and then selecting "System". Look at the upper area for the oprerating system name and look in the middle section for the processor, memory and system type. If the system type says "32-bit Operating system" then that is why you are seeing only 2.99 Gb of memory. If you want to see more memory than that then you will need to reinstall windows using the 64 bit version of the Windows 7 Ultimate installation CD.