Here's a thread about upgrading your CPU: http://en.community.dell.com/support....aspx#19970142 Your system has a 300W power supply, so you need a GPU that doesn't draw much power. Here's a thread about that: http://www.tomshardware.com/forum/33...w-power-supply (apologies for duplicate post)
edit: Here's a thread about upgrading your CPU: http://en.community.dell.com/support-forums/desktop/f/3514/p/19412399/19970142.aspx#19970142 Your system has a 300W power supply, so you need a GPU that doesn't draw much power. Here's a thread about that:…