W7 has many drivers built in by default. I suppose it is possible Sony strips out all drivers but what they need but if the only change you made was a harddrive then I cannot see an issue. To my knowledge internal harddrives do not use any special drivers so the computer should see one Sata HD the same as any other (an exception
might be if you break the 2GB limit because then sectors are formatted differently and the drive may need special handling).
I do understand it didn't come with DVDs; it is very common that you are told to generate the DVD when you first boot a new laptop. That is true of Dell and pretty much all laptops these days.
So as I said I do think there is something else going on here. What I don't like is that they are called "recovery media". It may be that it is looking for a hidden recovery partition which of course your new hard drive doesn't have. Often they basically put the W7 DVD on a hidden partition on the HD; if so and if all the recovery disks are trying to do is find that then they are a rip-off and the tech should have known they would be worthless on a brand new HD. You actually need media with W7 OS on it. I would definitely be trying to Tech support again because I would be royally torqued by now.
It can't hurt for you to burn that W7 SP1 and see if it will at least install. But you may still want to try and get the right Disks and/or setup instructions to use the disks you got from Sony.
NOTE: you may also need to download and install
IMGBurn in order to properly burn that W7 DVD. If you use software that cannot handle an ISO image properly then all you will end up with is a DVD with a single file ending in .ISO, so if you are unsure then just get IMGBurn and use it.