Find a PC running Win 2000 or less.
Put a DD floppy in the PC
Format it at 770k
Boot up Amiga
Open the Storage drawer, move PC0 into DEVS/DOSdrivers
and you should be able to move files back and forth from the Amiga to the PC.
If you have CrossDos or MessyDos, you can use those too.
Glad that the Amiga can still make you happy. :-)
edit: hmm. backup the HD. One way is to use the HDBackup program that comes with your WorkBench. Be sure to have a lot of floppies. Check out
www.aminet.net for other backup programs. I like Abackup personally.
If you feel daring, try and hook up an external CDRW to the 500 through the DataFlyer and install this
makeCD