System requirments? (Any tech guys here?)

[Amtath]

Might be a little bit late, but as I have used a 5450 on my htpc build. I can say it's definitely not made for gaming. It's no better than an onboard GPU. It's really an htpc oriented graphic card for old build where the GPU isn't strong enought for 2D HD content or for build that don't have an onboard GPU.
It's great for 2D content, upscalling and so on. It's cheap and as a very low wattage. The Hybrid Crossfire is possible only on a selection of motherboard. Not sure a Hewlett Packard has the options in the Bios for that anyway. I tried it the result wasn't worth it, a lot of visual bugs even on the desktop.

And for a graphic card hard to say what kind of psu you have, if you have the available PCI Express connector.

A 5570 or even better the 5670 would do better than the 5450, both doesn't require a PSU Connector. The 5570 is approximately twice as good as the 5450 in 3d and the 5670 25-50% better than the 5570. The price for the 5570 would be in the 60 euros range and the 5670 1Gb in the 75 euros range.