True that the "welded screws" are...... not really screws at all. We broke off the capped bits that hold the keyboard and cover in place. We then replaced the keyboard and used a glue-gun on each of the "screws" to keep them in place, effectively "repairing" each of the screws we had broken off (/ had "un-capped)".
This works like a charm. It was a few years ago, and I am using it still, including right now :)
Never saw such an insane design in a laptop before. It seemed a bit scary to break off dozens of bits in a laptop, but it wasn't in the end. Don't let this hold you back from repairing your (otherwise) awesome laptop!