Does anyone know any tips on recalling files, folders etc. from your computers hard drive, even from 2 years ago? I know it can be done with special tools/programs - i think. It sounds interesting? I would like to know how.

For fairly recently-deleted files, a program like Norton Utilities' Unerase can obviously be of help. For reading/recovering data that was deleted some time ago though, you're probably looking at spending some serious $$ for a professional data-recovery application, because the areas of the disk in which that data was stored have most likely been overwritten multiple times. Your chances of being able to "decode" the magnetic signature of old disk-writes diminish greatly if that's the case.

Of course, utilities do exist for reading/recovering such data; some of them only available to law-enforcement and other government agencies. Depending on your exact needs, your best bet would probably be to do some Googling for keywords such as: data recover format unerase.