I just installed an extra RAM but the Vista won't boot, should I change something in BIOS for it to recognize it and boot?

Did you check if your new ram is compatible?

The BIOS should detect your new RAM automatically.
If it doesn’t boot now, does the computer beep at you? Those beeps indicate a POST (Power ON Self Test) error.

Try removing the new RAM module and booting. It if boots, try your ram again. It may not be seated properly.

Also make sure you’re grounded. You don’t want any static electricity surprises.

Yeah it is the right RAM I personally went with my old one to bestbuy so that they will get me the exact kind.
Maybe I should try if the slot is working first somehow.

Try the new RAM in the PC and take out the old stick.
Does it boot then?