Remove all the heat sinks and anything else you possible can, preheat an oven to 385 (might want to use a thermometer and some thermal mass if your stove kicks

Remove all the heat sinks and anything else you possible can, preheat an oven to 385 (might want to use a thermometer and some thermal mass if your stove kicks on real hard so you don't overheat), make some tinfoil balls/pyramids and use that to elevate your card above the board, make sure most of the mounted components face up, cook for 10-15 minutes, VERY CAREFULLY remove it, or just turn the oven off and let it cool down again so you don't risk knocking anything while it is semi-solid, reapply heatsinks with new paste and install and test. Sometimes they need a bit more time or a few degrees or to be done more than once, but it works most of the time. Do not get your oven too hot or you risk causing components to fall off, it isn't actually reaching full melting point, just close enough for solder cracks and tin whiskers to self-heal. I probably don't need to say this but don't do this with a card that works because it is a small risk. The key is keeping a stable temperature and not rushing it. Ive never had it fail on me, but that could just be luck of the draw.