lol disable WoW using cp codes to close ports or something haha or block it w/ the firewall? idk how smart she is cause that could hold her off for a while if she's only 7

If she has a phobia, chances are you can find enemy monsters representing that - spiders, bugs, etc. Lead her there, making sure her hearthstone is off. Otherwise, I'd go with the 'showing her other things' idea. Or sabotage.

Candle, just tell your sister not to say what sex she is or anything like that. As is game may somewhat be addictive to some people. But you can limited her game use to WoW in account management so that she doesn't play it as much. Wait till she hits 70 and wants to start raiding thats where hell begins. 2 hours to 12 hours + spent inside an instance on a weekend instead of being outside. I'm sure she'll get bored of it sooner or later at her age. I myself limit my game-time on WoW to around 20 mins to 1 hour a day sometimes I never log on for few days. I have better things to do, hell I barely spend any time on pc these days.

Thats a lot of money wasted every month.

Get the account data somehow and get the IP banned by doing something stupid. I am an MMORP gamer myself, but even though I have not played WoW, I can keep control of myself...

Do all of her friends know? Embaress her about it in front of them, and any cute boy that might be around.

All you need is to put her next to a peer she looks up to, or crush, and have that person talk shit about nerds spending all their time playing video games having no life. full proof.

Try hooking her on Call of Duty 4. That'll save her! >:D

This.

Don't you think it would be better and easier to do that with TF2.

Or you could beat one addiction with another... >.> Get her hooked on drugs.

he means hooked on other drugs.

Nothing Special. I was hooked at the age of 3, when StarCraft first came out...

As for your sister, hax her accounts and disablez itz!
OR
Remove WoW Completely and fuhgetta bout it

... You were three when Starcraft came out? And I thought I was a youngin'...

I played at like, 7 or something. [StarCraft]

I guess gaming starts young.

My little bro played starcraft at 4. He sucked balls then, still sucks now. Solution: Give her breast implants and sell her to a pimp. She'll come crying and stop playing WoW if you buy her back.

Uninstall it and hide the CD Key so she can't reinstall it. Or go on her account and get her perma banned.

Keep deleting the character data files and say that the game has glitches.

You guys obviously don't have younger siblings, she's 7, she's not afraid of anything, if something goes wrong it's always my fault, she is NOT going to end up raiding at 70, don't even joke that she will because she won't, she's only interesting in WoW because the rest of my family plays it as well (9y/o 11y/o and my parents) I don't think any of them will 'get over it' and she will NOT just get bored...

Well since you can't sabotage the PC, and that your whole family plays WoW, you could either:
1. Show her something much more fun to do

OR

2. Tell her the stuff NOT to do when playing online, specially because she is A 7-YEAR OLD GIRL