Hi there and welcome !
I'll have a check but I think you are going to need some System 7 disks...
Where are you based ? I have System 7 disks, but there may be some one closer to you, or a local Mac User Group that may have them.
I thought you could download System 7 from Apples website now. But I can't find the link, this
one has all the updates, but not the 'actual software'.
I'll have a look later to see if I can track down the link.
Have you tried starting it with the Battery out and just the AC adapter plugged in...
I have one of these somewhere I think...I'll have to have a look.
regards
Ric