Could I load the Playstation OS on a computer hard drive, and play with a controller?

Solution 1:

Short answer - no

PS3 has a completely different hardware, different cpu architecture, different everything.
Theoretically, you could emulate the PS3 hardware, but you would need an insane PC from the future and you'd also have to code the emulator, because no one in their right mind is going to bother with that in the nearest 10+ years. It's the reason why even PS2 emulators require fairly powerful PC, even though the PS2 itself is ancient by today's standards.

Solution 2:

Apologies for the necro bump, but there is now official software released by Sony called PlaystationNow that allows you, with some guidelines and a subscription, to run PlayStation titles on your PC

Solution 3:

There are a few technical problems that would prevent this:

1. The PlayStation uses a Cell processor as its CPU, which is based on the IBM PowerPC architecture. Windows doesn't run on Cell processors.
2. The PS3 encrypts the hard drive. You can't even switch a PS3 hard drive between different PS3s without reformatting it.

Point 1 also makes it harder to emulate the PS3, as a Cell processor has 9 cores (one for the PowerPC chip and 8 for the SPUs).