I just got my first good video card but the only pci cable I can see is plugged into the mother board?! Are there more in the case?! What is this, I'm getting scared, please someone help.
It appears that you have a shitty oem prebuilt with a low quality power supply. Don't even try to turn it on unless you want to destroy your hardware and set your house on fire. You need to invest into quality PSU to start using your new card.
also please educate yourself before posting
PCI-E power cables don't plug into the motherboard, however other 12v connections, such as the ATX 20+ pin and ATX 4+4 pin (CPU) connections do so.
Your PSU may still have viable connections to power the card. Do you have any 4-pin molex connectors?
These are not idea, but your video card probably came with the necessary adapter to connect the Molex cables to the PCI-E sockets on the card.
Since you apparently did jack shit research beforehand, this might be a good time to check that your PSU can deliver sufficient wattage and amperage across the 12v rail to power the card. You'll usually find the numbers on a sticker on the PSU.
If the photograph is your computer, then it looks like a shitty prebuilt, which will almost certainly contain an anaemic PSU with just barely the right connections to get it working with the stock hardware configuration.
If you have £50/$75 to spend on a new PSU, then great, you should be able to find a good quality PSU for that price that will provide you with everything you need and come with a good 3/4 year warranty. If not, then I suggest returning the current card if possible, downgrading to a 750ti, and getting yourself a decent PSU before considering any further upgrades.
Then what is that???
I think I can just about make out the Hewlett Packard logo in that poorly lit room, through the lens of your potato, which you're photographing at an awkward angle.
If you can't afford a lightbulb or a decent camera, and you're buying a $200 GPU then your priorities are all kinds of fucked up.
You have a low tier PSU that is lacking extra (or maybe any) spare PCI power cables. If your cheap look up a $35 psu with the cables it something. Better than the dude suggesting a converter the current PSU probs not powerfull enough to last long anyway.