Radio Receiver on my PC?

OK I know a little bit about radio (TX/RX AM/FM HAM CB etc.) I've built a few FM transmitters in my time and messed about with receiving signals with both professional kits and also with home-made antennae / random wires connected to little oscillator amplifier circuits. When I was 10 (lol) I picked up lots of Spanish / Dutch AM stuff just by putting a long piece of wire on my water pipes and then connecting a pair of old headphones - seems the magnetic coil was enough to amplify the signals into audible currents!, I've also used Wi-Fi / microwave links, I've not really looked at I.C. chip radio receivers except I know they are used in some walkman phones and so-on (basically they work OK with the right power source, antenna etc.) My question is, knowing that you can simulate I.C's on a PC using electronics software, is it possible to create a software radio receiver program (FM or AM) on a PC that produces audio output and is "programmable" in terms of frequency etc.? There is an I.C. TDA7000 and U4065B which seem to do the job, and I was wondering if the logic could be simulated on a PC effectively,. Is there any theoretical reason why software alone would not be sufficient to give the same (or similar) logical output which I could then rig up to some kind of DAC software to actually hear the radio waves... In other words they are demodulated by virtual instructions held in my PC's memory, with the CPU carrying out the IO control? OK I know you can get PCI addons and exotic USB radio thingys dongle stuff but my point is it must be software, not hardware. This would also need some kind of antenna - well, my guess is that WiFi uses a built in antenna in my laptop's screen, my desktop has an external antenna - so really I can't see why a decent CPU like Intel i3-330m can't actually emulate or simulate these logical FM receiver I.C's, even if it meant setting up some kind of platform for I.C. architecture?.Man sounds crazy but I just can't see any reason why it cant be done - so, my CPU does things by Fetch-Execute cycle etc. ~ it's step by step but surely that can simulate a continuous signal from an IC? could I code something in C++ or Java which reads the antenna, breaks the signal into the desired frequency range, demodulates it according to my wishes and then converts it to audio output? , or would I have to resort to a physical add-on? for all you Computational theorists out there... sounds simple, but it ain't for some reason, any light on this topic or similar IC simulating stuff v. welcome Thanks