Could I install a new GPU on this?

For a couple of months now, I’ve been thinking of building a pc but I’m still scared I’m gonna do something wrong and waste hundreds of dollars. I just found a good deal on a core i5 with 6 gigs of ram but no dedicated GPU for $499. If I bought it, would it be possible to install a new GPU?
http://www.staples.com/Lenovo-H420-Desktop-PC/product-nr_441385

Link’s not working.

I encourage you to do some research and build from scratch, even if you buy the parts and pay the store to assemble it for you. There are many forums online where you can post your ‘final’ system parts list to get feedback from people with far more experience, just to be sure you’re getting everything to match up properly.

It’s tempting to buy pre-built from the big name PC companies, but you end up with hardware designed for very specific needs. The H420, for instance, is meant to be used for general office work. That means low power, likely built-in video and sound and a scarcity of PCI slots. It’s highly unlikely it’ll have a 16x PCIe slot, for instance, which is what you want for that fancy video card.

Even if it has a 16x PCIe slot, you’d have to be careful not to exceed the power supply’s output which means you’d be fairly limited in how far up the video card upgrade path you could go.

If you want to buy pre-built, buy used. Somewhere near you there is likely to be a store that deals in lease returns. For the same money, you could get a used IBM Intellistation or Dell Precision workstation, something designed for high-end graphics. Lease returns are a pretty safe bet; they aren’t like cars where abusive driving habits have to be taken into account. Office workers don’t overclock and name brand computers are designed to be left on 24/7. Just make sure you don’t go too old; you’ll still want a 16x PCIe slot for the video card upgrade.

Whatever way you approach it, you’ll need to do some research to make sure you’re getting what you’re aiming for.

Good luck.

Thanks rontarrant for the reply
I just found out that it has a really weak power supply.
I think i’ll wait a little longer and follow your advice.