you know, I was on CM9 and decided that I would perform a nandroid restore back to CM7 today. So I booted in CWR, wiped both data, cache and dalvik cache, did the nandroid restore and rebooted. It came up and everything seemed fine at first. Then my signal went away and I couldn't *228 which was weird. I went into the wireless settings and tried tinkering there and nothing was happening. So I rebooted the phone twice and the second time it came back. Working great now!
The next thing was that my sound was not working. No music, ringtones, youtube, etc. Did another reboot and voila, everything came back again.
If rebooting does not help then I would suggest wiping cache and dalvik cache. If that still does not work then I would SBF back to 2.3.4 and redo your CM7 flash. I'm going to do the same in case I get further errors.