Mad_As
To asnwer your questions:
1. Errors playing, it's best to format it, but since you said you've formatted it already, it might be a bigger problem. What did you use to format your player?
2. Follow the Knowledge Base article "How to: extract firmware of your player using the S1fwx tool" from
here. That will extract the firmware that is on your player currently. However, it is only meant as a partial 'backup' and not a FULL extraction. The only way to get a 'full' backup of your firmware is to look in the cd and try to find any .fw files.
3. .7z files are just another compressed file. You can download 7zip from our [Downloads] --> [Tools] section.
Now, a question for you, what size players do you have? As this might be the root of most of the problems you're having.