The Siam-er lurks again

Sickening Siam-er aka fellow colleague is getting on my nerves AGAIN.
She spoiled my evening gathering dinner with my colleagues as i had to stay back.
A simple bloody thing which she could do it on her pc but in the end i had to do it since i was the last person who knew how to use the system(the other colleague left the company).
Bloody Hell! I taught her before and she conveniently forgotten how to do it and it is within her job scope.
Makes me wonder what does she does all day!!
A total BITCH i have to say.
Work alongside with her and you'll experience it and i'm not first one who said so.