You have Acre Aspire computer with an AMD Athalon 64 3500 with 512mb ddr2 will it play Oblivion okay

Read the system requirements for the game. The critical factor is not the computer speed it is the graphics card. If you have a separate one with 128 mb memory or higher, it should play but only at low resolution. Nvidia 7600 or higher, ATI 1300? or higher.