Glad to read that someone used brain after accident (removing battery, rice, etc) and sad to hear, that device seems to be somehow damaged.

Still, it's a pity that You hadn't googled for "disassembling" video - it's relatively easy process on N900, and separating parts as much as You're willing to disassemble them, would help in drying. Your keyboard leds seems to be somehow affected - personally, I would try full disassembling and covering it with silicon gel (instead of rice - silicon gel is cheap, available in good camera stores, and can be re-used), it's much better @ absorbing humidity (be sure to use air-tight container, or you will absorb humidity from room air, instead of N900). I'm not sure if there is a point to do it after such long time, but even if there are slim chances of it fixing anything now, IMO it's worth a try.

I suppose You were not using backupmenu, so Your only way to go now is flashing (see wiki article reflashing). If that doesn't help, try with R&D mode - maybe watchdogs are kicking in, due to some elements being damaged (leds, led-controller goes berserker?).

And, while we're talking about booting - You mentioned leds, so at least boot is proceeding to the point of loading their drivers. I suppose, that it's doing full initial boot, as You can see five dots. Still, it doesn't mean't that for sure everything will be all-right - You may have, for example, eMMC damaged (thus optfs not present), but for sure You're not screwed totally. Basically, don't get desperate, but also don't get hopes too high.

Good luck and report back, how it goes/ended!

/Estel