You've been fed a pack of crap by Acer/gateway. Half of the information you have is wrong and their information is wrong too.
You can't pair a Core i5-4440 with a Socket 1155 motherboard. The Core i5-4440 belongs to the LGA 1150 family.
On top of that your current board comes with some kind of weirdo 12-pin ATX power connector instead of a 24-pin connector like the rest of the world uses. It might be possible to find a 12-pin to 24-pin adapter but it's not recommended. If you get a different board, which will have a 24-pin ATX power connector then you're going to have to buy a new or used ATX sized power supply that has a 24-pin connector.
3rd is this HUGE fallacy that a Socket 1150 board uses a b75 chipset. The B75 chipset belonged to the socket 1155 family but those boards only work with Core ix 2000 and 3000 series 2nd and 3rd Generation processors, like a Core i5-3450 or Core i5-2400. It's a well known fact the Socket 1150 boards use the b85, h81, h87, h97, z87, z97 chipset, not b75 chipset or any 70 series or 60 series chipset.
The DX 4480 desktop comes with an LGA 1150 motherboard with a b85 chipset. I have no idea where you got the idea that you have a Socket 1155 board. I have no idea why sellers on ebay or cnet keep saying it has a b75 chipset and I can see where this confusion is coming from. Like I said and I can't repeat this enough, The Intel Core ix 3000 and 2000 series processors pair up with the Socket 1155 boards. The the Intel Core ix 4000 and elusive 5000 series processors pair up with Socket 1150 boards. The Intel Core ix 6000 and 7000 series boards pair up with the 1151 socket. This is not counting the LGA 2011 or LGA 2011 v3 HEDT parts like the Core i7-6800k or Core i7-3930k.
Those boards are almost always mATX sized boards and they're all interchangeable for the most part. You could buy any one of those brands. Personally I'd recommend avoiding the HP, Acer, Dell, Biostar, ASRock and Intel boards because the quality sucks. Companies like HP, Dell, Gateway/Acer use boards from other companies. HP has been known to use Asus.
If you want to avoid any software problems and you want to be able to use your system without reformatting then buy the exact same motherboard. You may have to reenter the product key.
If you have to go with an offbrand then look at Asus, Gigabyte, or MSI for a board. Before you buy one, make sure the dimensions of the board you're buying match up with what you already have. The size of the board you have should be 9.6" x 9.6" but it's worth a double check.
If you go with an offbrand board, the drivers loaded to your OS may have troubles and the system may not work at all or it won't work correctly. You can simply reformat the system. Hopefully your system has the product key sticker on the side and that would be most useful. You can actually use a Windows 7 product key on Windows 10. If you have to burn a copy of Windows to a DVD or Thumbdrive, you can use the 'Media Creation tool' for the version of Windows you want.
If you don't have a product key and you get stuck you have 3 options. You can used Windows 10 without a product key and sometimes logging into your outlook account will fix this issue. You can spend nearly $90-130 on an new OEM Product key. The last option is you can buy a flipped or refurbished key off ebay for around $15 to 25 dollars. These key are either pulled from broken systems then resold because they have little value or they're resold buy people who have bought a bulk amount of product keys. The thing is these flipped keys aren't supposed to be sold by these people so it is possible that your key could become deactivated over time if Microsoft does an audit. The reason these people are able to get away with this is Microsoft does a very poor job of enforcing their product key rules.
At the end of the day, it would be cheaper to find some socket 1150 board and buy something like an EVGA 500w 80-plus white power supply and call it a day.
This confusion caused by Gateway/Acre over what parts they're using, the confused resellers who have no idea what they're selling, the junk parts, and the proprietary power connections is the reason why it's better to build your own PC. I've been answering questions for 6 years and have never seen such a sh1tshow.