On the White MacBook (Late 2007 Santa Rosa) A1181
13" / 2.2 GHz / 2 x 1GB RAM (DDR2 667) / 120 GB HD
Still unable to boot it...
1) Used a known working AC adatper to try to boot it (didn't work)
2) Tried starting up with and without the battery, only with the AC cord
3) Charged the Battery (charged successfully) with another known working White MacBook
4) Tried your procedure for starting up with RAM Modules removed one at a time (even cleaning gold connectors, trying other known-working RAM Modules, and making sure they are seated correctly)
All to no avail...
I have not tried the magnet thing...