Actually, I wasn't able to figure out, what your current problem is, so I'll have to answer to what I guess it might be.
First of all, you should have used sysupgrade to flash your board, as I suggested earlier.
That being said, let's have a look at your other (possible? As said, you were not very clear about that) issues:
- no wlan device showing up: most likely you forgot to comment or remove the "option disabled 1” line in your /etc/config/wireless
- no lan connectivity using virtualbox: to connect to the guest, you will have to add a port forwarding in virtual box for the service of the guest you want to connect to [TFTP listens on port 69, you'll find the forwarding options on the network properties page of your guest VM in virtual box], and may have to add an according exception to your host's [the windooze 7, that is] firewall
Also, your board won't be dead until you'd manage to damage the boot loader - you'd almost always able to reflash it.
But you'd really start a bit smarter: if the IP connections won't work [thus, the sysupgrade flashing method being unavailable], you should try to fix that instead of going to the next lower level (serial, boot loader 'n friends) or otherwise I already see you desoldering and replacing the flash chip in the next iteration of this approach
Report back your proceedings - I'll try to help again, if I happen to read an update here.
