Any idea how she did this or to fix it.

I'm attempting to fix my sister's computer (not easy being 150 miles away). Some how she seams to have changed her administrative account to a guest account, or so she claims. With our hectic schedules we've only been able to do e-mail tag on the problem but I don't even know how that's possible. I asked to confirm it's not a standard account and she insists it's shows a guest account with her name.

I believe she's running win 7 home 64 bit. Part of my confusion may be my only win 7 system is Pro.

I hope to get more information, maybe even a remote assistance into it this weekend but but I wanted to put it out there and see if this sound familiar to anybody so I can hopefully go in with some ideas what she did, how she did it, and how to fix it.

She really needs to get help from a Malware forum. Here are two excellent forums.
http://www.bleepingcomputer.com/forums/forum103.html
Virus, Spyware & Malware Removal - What the Tech

She needs to only choose one, because they will only help on one, not both.
Just register and post the problem.

What about my description makes you think it's malware?