OK. So you want to run Disk 1st Aid or Norton Disk Doctor or Speed Disk, but you've only got one Hard Disk...

Here's one way around the 1 disk problem...

1. Quit all your applications
2. Use your Memory control panel to create a RAM disk that's about 5MB. (You'll need to reboot to get the RAM disk initialized)
3. Install a "Minimum System for your Macintosh" to the RAM disk.
4. Use the "Startup Disk" control panel to select the RAM disk to start from.
5. Restart. (RAM disk contents are kept through Restart, but are lost when you Shut Down.)
6. Run Disk 1st Aid. (& Repair your Disk.)
7. Reselect your HD in the Startup Disk control panel.
8. Trash and delete the System on the RAM disk.
9. Turn off the RAM Disk. (I keep a 1.1MB RAM Disk Active to use as my Netscape Cache)
10. Upgrade to System 7.5.5.