You have 1x PCI-E x16 expansion slot so yes you can , however I can't find your PSU model or output, could you open up your case and look at your power suply picture and tell us how many watts you have, then we can suggest one
but he has a PCI express slot!, he could upgrade easily, it just all despends on his power suply. He might not have the funds for a new computer. Please don't give answers like that, It's uninformed and not productive.
OP could you please try and check your power suply for me, you will be able to upgrade the graphics card easily