if you press F8 on bootup can you start up in safemode? or does it still just go to black screen? (or whats the last thing it does before going to black screen?)
If you can't boot up in safemode either, its likely something has gone wrong in the hive files. To fix this you can boot up via a windows cd, login to the recovery console and go to your windows directory and cd to a hidden directory called repair (cd c:\windows\repair\) then copy these files to the C:\WINDOWS\system32\config directory (you might want to try copying everything EXCEPT the software ones first and try that, then if unavoidable copy the software ones if it still doesn't work).
These are backup hive files when the OS was installed. Essentially that should allow the computer to start up, however it will unregister drivers (video/sound etc.,) - they're still on the system, so when the computer starts you should be able to run through the device manager driver updates pretty quickly.
The software hive contains registry keys added by software, so if you have to restore this you'll probably need to reinstall your applications which is a ballache, however if the computer is stalling on startup, it's more likely a system (driver) or security hive issue.
------
Assuming the memory card is either virused or corrupt but is still mountable as a drive, have a look at software called file scavenger (it's old and clunky, but I've used it for years as it's proved very functional)... technically paid for software but am aware it's available on the torrents. If it is a virus I'd recommend trying to recover the files first then run an AV scan on both the dodgy camera disk and the recovered files (as AV tends to be a bit trigger happy deleting stuff
)