Q: Startup Trouble with PowerBook 170

I still love and use my 1992 vintage PowerBook 170 nearly every day for word processing (Word 5.1a). The black & white screen is easier on my tired old eyes than my newer color PowerBooks and it keeps me from surfing the internet and wasting time.

But recently I've been having start up problems when I boot it in the morning. I get the flashing question mark every time. BUT if I just touch the computer, press on the case, or move it slightly something usually jars and then the question mark goes away and it starts up normally from there. It doesn't seem to matter where I touch or press on it. At least I haven't found that place yet. Just the touch itself kicks something in and it boots up normally and the flashing ? goes away.

I had it apart but everything looked good. I made sure the main flat cable with the weird bend was plugged in fully. Otherwise it seemed okay, altho something must be amiss. To me it seems like more of a hardware than a software issue. Also, in the past sometimes the pixels on the screen would not all work properly and the text was garbled and nearly impossible to read. But again, by squeezing or pushing on the case the pixels would snap into operation and everything was normal. Back then the 170 booted up perfectly everytime. Now the pixels all work right but it doesn't want to boot. Now I get the flashing ? everytime altho so far I can jostle it and make it start up.

Any idea what I might look at to fix?

PS: I've run Norton Disk Doctor on it and the hard drive checks out OK.

Thanks!