I have a half-mini PCI-E WiFi card (RTL8192E to be exact), which has 2 small aerial pins plugged into it. Can I use this without any aerials in a new PC build so I don't have to buy a new WiFi card? If it will work, would the signal be strong enough to reach to a router which is downstairs, pretty much directly below me?

Thanks,
--Mark

im Gonna say no ,its will need the antanas ,but you have it so plug it and find out if it will work ,cant brake anything tying

Most of these cards have built-in antennas, but provide external antenna leads so you can install better or high-gain ones for better distance and performance.

you would be lucky to get a signal more than 10 feet from the laptop