Stacia G@ ! !
Unfortunately some kind if system changes, including setting the clock back, will cause the trial to end early. That's it for that computer I'm afraid. The $30/month plan can be cancelled at any time, so you can use that to evaluate. Cheaper plans are a year commitment.
If you want to learn Photoshop there are some very good books available such as the Classroom in a Book series and the QuickStart Guides. There are also some excellent online video tutorials from Lynda.com and Pluralsight.com – you can get a 10-day free trial to both of these. And there are free tutorials from: http://tv.adobe.com/product/photoshop/
And of course you can ask specific questions on this friendly forum!