First of all, If you haven't done it already, I will recommend that you download & install a file manager utility since this makes managing files sooo much easier. Personally I prefer Filemaster, but DOpus is also an alternative. Both can be found on Aminet.
For your "please insert volume 68E6-6B70" problem, I would suggest that you check if 68E6-6B70 is mentioned anywhere in S:User-Startup or S:Startup-Sequence. If you find something there, like a line beginning with "Assign 68E6-6B70:" or something similar, disable the line by inserting a semi-colon at the beginning of the line. If you can't figure it out, a quick and easy solution is to add the following line at the top in your user-startup:
Assign 68E6-6B70: Ram:
As for the "Intuition is attempting to reset the workbench screen" problem, it is probably because something in your WBStartup drawer is launched before Workbench is properly started.
As "clint" said, be careful what you delete, and I would also recommend that you have an alternative way to boot your Amiga in case you mess up things so bad that Workbench refuses to start (one example being your Workbench floppy), this way you can try to fix things more easily.
