Depending on what your requirements are, there are some popular lightweight Android Emulators present on the web that can be used on a low-end PC with 2 or 4GB of RAM and a below-average video card.

source: Gamingsym

For Gaming: MEmu

Specially made to play Android games on PC like PUBG and COC, etc. Stable and filled with features like you can capture screenshots and record video at one click. This emulator allows you to manually allocate resource for running this emulator and also change the resolution making it more resource friendly during heavy workloads.

For Multitasking and Productivity: Nox Player

Nox is the most lightweight Emulator I have ever used on a PC. Its download size is just 350MB and is very resource-friendly. Packed with some cool features for gaming like custom key mapping and instant access to brightness and sounds which are quite handy. Nox player is also energy efficient with my battery lasting noticeably for quite a long time.

If you completely want to turn your PC into an Android device try Phoenix OS. You can also dual boot your PC. It has windows like UI with file manager similar to windows explorer(drag and drop to move or copy files) and performs pretty well than my expectations