MacBook Pro(blems)

Hi there:

I have an old 17” MacBook Pro, 3.06GHz, Intel Core 2 Duo, 4Gb Memory, 1067 MHz, DDR3, purchased September 2009.

It was running Mac OS Sierra which was as far as it would update but a couple of weeks ago, it crashed and wouldn’t reboot. After reading a couple of forums, I was able to restart it and reinstall Sierra which it did up to around 95% complete, then stopped. So I dug out the only OS discs I have, Snow Leopard and after verifying, repairing and eventually, erasing the hard disc, I clean installed Snow Leopard (via an external disc as the internal CD-drive hasn’t worked for years). My intention was to immediately update it to the latest OS (presumably Sierra again).

The Mac now starts up and does its little animated Welcome movie then requests a few registration details. Depending on how quickly I fill in this info, either during or soon after, the ‘spinning beachball’ appears and that’s as far as I can get. I can’t force quit, I can’t use anything, the only option is to force shutdown. I have re-run the verify disc option from the installation disc which always reports no problems and I’ve re-installed Snow Leopard but always the same result, the spinning beachball and a force restart. 

I’ve also tried rebooting in safe mode but it gets no further than the grey screen and apple logo.

My Mac knowledge is not great but if anyone has some step-by-step advice, I’d be really grateful as I’m getting nowhere. Many thanks, sheffgraph