Car Wont start

[bloggs24]

I have got a au2 xrs vct i recently changed the lash adjusters as they were rattling and i forgot to fill the new ones with oil, when i started the car it ran but the lifters were very noisy so after a week without driving the car i decided to remove the rocker cover and fill the lash adjusters with oil through the little hole above them, while i was doing that i decided to paint the rocker cover.
The next day when it was fully dry i bolted it back on and when i attempted to start the engine it ran for a couple of seconds then died and then whenever i attempted to start the engine it makes a clicking noise then nothing happens. I noticed the battery was fairly low and has now gone dead, possibly from attempting to start the car.
Besides the battery what could have possible happened, i plan to pull the rocker cover off again coming weekend. While noisy he engine ran fine after my first attempt at replacing the lash adjusters, all i had done on my 2nd attempt was fill with oil through the oil hole above them.
Any help with finding what could be wrong would be appreciated, Im not a mechanic but im fairly mechanically enclined, im stumped as to what he problem is.