Connor,
In the past, i've been able to fix problems with RAM by removing it (with the power off, of course) and reseating it in the socket. Sometimes, heating and cooling with cause the RAM to slowly move out of the socket, so reseating helps.
Make sure you touch a metal part of the computer case to ground yourself and reduce ESD, which may damage the RAM, before you remove it. If you must put the RAM down, do not place it on a metal or plastic surface; place it on a sheet of paper to protect it from ESD.
If reseating does not work, try purchasing a new 512 MB RAM stick of the same kind (e.g., PC 100, PC 133, or whatever your motherboard requires).
If replacing the RAM does not fix the problem, it is some other hardware that is at fault, as GX1 suggested. (For example, a power supply that is failing to provide enough wattage to satisfy the system may produce a 0x50 error.)
Best regards,
Doc