So one of my arduino's has started acting funny, and I'm not sure what to do since the troubleshooting page doesn't seem to mention it.
When I first plug it in, via 9v or USB, the sketch won't load and the L LED flashes three times rapidly. When I upload the sketch to it again it seems to work fine, until power is removed. Plugging it back in, and I'm back to square one. I'm still very new to this, so any help would be greatly appreciated.