I last used it about a year ago, a 520c with (I think) 4mb of ram and some flavor of system 6 or system 7. At the time, it booted with no problems.

Today I booted it to make sure it worked before I went to install Sys 7, but I got nothing on the screen, just white. Tried taking the batteries out, putting them in, attempted to boot from a disk tools disk, but still nothing. I have never had to troubleshoot anything with System 7 on it. Where do I start?