|Are you saying you removed the RAM stick, then re-installed it - and now the laptop won't work?|
When you removed the RAM... did you ensure that not only was there no mains power going into the laptop, but that you also removed the battery? This to really ensure that there was no power at all in the laptop when going inside it...
And have you tried to remove and then re-install the RAM stick (card)?
And what does this mean: "...I know my HDD is borked..."?