Yes, there is a device. It would be called a "capture card".
For example, the Blackmagic Design Intensity. It has HDMI inputs, will capture HD, and will process uncompressed HD as well. You also didn't say anything about your actual computer (desktop, laptop... available slots in a desktop, etc) which would NORMALLY present even more of a problem suggesting a solution for you, since how can we know what kind of computer accessory to suggest, if we don't know what kind of computer it is for... right? But in this case, the Blackmagic also has three different versions. Two are portable and will connect to either desktops or laptops... one is a PCI-E x1 card.
Now. Is this the ONLY device out there? Nope. Just one. All I did was use a search engine to look for HDMI capture card. Yep.
Here's another one. The AverTv. It also has HDMI inputs for HD capture.
Starting to see how this works? There are lots of HDMI capture devices out there, and they are actually kind of easy to find.
Now, if you were asking about some stand alone device... then I'd expect this question to be closed soon, as you aren't asking about computer hardware. Actually, it will probably be closed any way due to the facts that it is really just a shopping question, and one where you didn't do much research on your own first.
Regarding Software... once you have captured it, you aren't needing to convert a rip. That's very different. Once it has been captured (like making a 1-to-1 dub copy), then it is just a matter of converting it.
But Oliver is right. You need to detail how you have failed previously and with what software you failed. What you want to do is not something simple that you can plug and one step.
EDIT The more I think about it, the more Bob is right. Just get a Blue-Ray optical drive for your computer.