That's sometimes true and sometimes not. Many IT people I know are finding themselves in trouble because they haven't kept their skills up or because they've followed a career path that led down a dead-end. I'm sure that folks in banking who specialize in mortgages are sweating bullets right now, especially if they work for HSBC's mortgage sector.
If you are interested in getting an admin assistant position, I'd recommend taking courses in WORD and EXCEL at ECC or NCCC. While a student, buy MS OFFICE through the bookstore (it's a major,major savings), and use them both until you're proficient in them. I think the courses are probably offered through their Continuing Ed/Credit Free course offerings (which don't cost a lot and don't take a long time), and proficiency in those is a good way to convince employers that you're serious.
I would definitely NOT omit the Masters degree if you're listing your education. You might decide to leave off your education completely, but don't leave off part of it. If you get a job and your employer finds out that you left part of your education off, he/she might feel you lied to him/her.
The same with your experience. If you feel that it makes you less employable in a new career, then trim the details and just leave it as:
1999-2001 AAL Organization Counselor
2001-2005 XYZ Organization Program Manager