ooooh. Welp I feel moronic. thank you.
Actually, to NOT ask the questions, ... would be moronic.
I can see by the pic of your motherboard, that you have a MSI 7778 v1. I took a quick gander at that motherboard on google, and it appears you 'should' have a dual cpu with anywhere from 1-4 gigs of ram. There are a couple of options that you have, but keep in mind that a lot of video cards require at least 500-550watts. I would imagine (knowing HP like I do), that your power supply will not be in that range. Not having an adequate power supply will result in many odd, strange things. Constant shut-downs or the dreaded BSOD's. If you are interested in other options outside the video card:
1. Your current system info is? (for instance, if you have Windows 32bit, it might not do you any good to upgrade to 4gig memory)
2. What are your reasons/intentions for the upgrade? (if you are going to be a gamer, the video card you choose might make the game more immersive)
3. Your spending budget? (see question 2 above)
4. Working knowledge on computers? (willing to jump in and learn - which can get complicated and risky)
I would suggest checking out WHAT you have, before going forward and upgrading. There are a couple of programs that I use quite often to check whatever PC I'm working on. You can choose either SPECCY or HWINFO (just use your favorite search engine, but d/l from the publishers site, or a trusted host.. to be on the safe side). I love SPECCY, but I sometimes it fails on 1st boot, but a 2nd boot is perfectly fine. HWINFO has a ton of stuff to look at, but can be a little intimidating too.