Yes, the RAM within this desktop is user upgradable. This model ships with 8GB RM (2 x 8GB). The maximum RAM this system can support is 16GB DDR4-2666MHz RAM. There are two RAM memory slots.

That will depend on the requirements and compatibility of the game. We recommend you check with the game's software publisher's web site for their compatibility with Windows 10 S-Mode 64-bit operating system (This model ships with Windows 10 S-Mode Operating System. Windows 10 S-Mode provides added security by only allowing APPs available ( and therefore certified by Microsoft) at the Microsoft Store. If you don't need the added security or you need to install APPs not available at the Microsoft Store, you can switch to standard Windows 10 Home 64-bit Operating System, at no additional cost.) and the minimum/recommended hardware requirements (Is a Graphics card required, the processor speed and the minimum required system RAM and the minimum available hard drive space) to run their program, then compare those requirements to this system's configuration.

Yes you can.

The Lenovo IdeaCentre 510A Desktop, model number 90HV001MUS ships with integrated graphics processing within the Intel Core i3-8100 processor. It is the integrated Intel UHD Graphics 630 version.