After about 4 months of no use I fired up my Pi today. The first thing that I did after booting was to run 'apt-get update' followed by 'apt-get upgrade'.
The upgrade took a really long time, almost an hour. I appeared that almost everything was being upgraded, including the kernel. During the upgrade there were some errors stating that the kernel upgrade could not occur. After the process was finished I rebooted OK and then after the reboot repeated the process which appeared to do the kernel upgrade without error. After this was done I rebooted again. Then the problems started.
The Pi would not reboot, just black screen. At first I thought the SD card was corrupted but when I looked at it on my Mac the boot partition was there, however there was only 4 files in it (config.txt, cmdline.txt, issue.txt and start_x.elf). In an attempt to fix this I copied all of the files from another SD card I had (also Raspian, created by NOOBS, but an earlier version). Since doing this I am now able to boot from my original SD card but there are lots of errors during the boot, suspect due to incompatibilities between upgraded components and the old kernel. My USB keyboard no longer works and the Wifi dongle also does not work. The only way I can get access is via ssh login through the ethernet port.
Is there anyway I can run a repair on the SD card to fix the Raspian install and make all the files consistent with the version? I spent a lot of time setting this card up with lots of really useful stuff and I don't want to lose it all and have to start again.
Any help would be appreciated.