I have these two songs, and I should know how to do this, but I can't seem to change the strumming enough to make the music sound all that different between them. Plus it doesn't help that the chords are exactly the same and even in the same order.

Its probably hard to give any ideas since you don't know the strumming pattern or anything, but.......
Any suggestions?
Learn to play the drums. When I learned to play the drums it made my strumming hand learn different patterns. (pssst... you also don't actually need drums to learn how to play basic drum patterns, just use your desk or a table along with online lessons). Although actually using a real drum set is preferable it is also much more expensive.

In addition, I would add that you should use different chord variations rather than playing Power and Major chords all the time (sorry if this assumption is incorrect). Throw in some Minor, diminished, maj and min 7ths, etc. Knowing your music theory helps to know when to use each of these variations.
Stop whining and learn your theory!

Quote by oddhawk676
Yeah, some black guy with a yankees cap walks into the ice cream parlor, and I said "We dont serve your kind here," as in, yankee fans, i guess he thought something else and left.