You're misinterpreting that information. You only have 768MB of physical memory
(actual RAM). The 2GB number is the swap space. You have one half GB of
physical memory available after booting. Loading one application will use that
up in short order. Then your system starts using the swap space. And, if your
swap space is on the same physical hard drive as your primary storage and boot
partitions, you're going to have a very slow system, one that will go
non-responsive on a regular basis.

Recommendation: Get some additional physical RAM.