Please help me about my computer?

[Dell Inc.]

REVISE,

Unfortunately, there is not much you can upgrade on this system. You can increase memory to 8 gigs. Below are the memory specs.
Memory module connectors Two SODIMM connectors
Memory module capacities 1GB, 2GB, 3GB, 4GB, 6GB, 8GB
Memory type 1333 MHz SoDIMM DDR3
Minimum memory 1 GB
Maximum memory 8 GB

Your system has the onboard intel graphic card. You cannot add another video card to the system. Below is an explanation on why the memory varies on your system.
Dynamic Video Memory Technology (DVMT) determines the amount of system memory allocated to video depending on how much memory is installed in the system. The allocation depends on the operating system installed.the maximum amount of system memory that can be allocated for use by the graphics controller. Your system can allocate up to 384 MB for graphics if needed but may use much less. The typical number is far below the maximum unless the system is running a graphics-intensive program.

Thank You,
Dell-Jesse L
Dell Social Media and Communities