The machine is quite weak since it only has a dual core CPU. This will limit you when it comes to gaming and running many applications. What you can do though if you dont want to get a new machine is upgrade the graphics driver to the latest one supporting your old Geforce 6150SE chipset
>>here<<. You can also upgrade your ram to the max it can take. You can use
this tool to help determine how much and what RAM to purchase. I also recommend possibly clean installing Windows (wiping it completely and starting from scratch) since that usually gives a nice performance boost. You can check out how to do a clean install
here. Keep in mind, if you upgrade from 4GB to something more, you will need a 64bit OS, or else the OS cannot take advantage of the extra RAM. You can download a legitimate copy from
here. You can use the Windows 7 key pasted on your machine.