I just recently programmed it to control my vcr and tv and now it does not change channels on the satellite reciever or bring up the guide or menu features, rendering it virtually useless. Has this happened to anyone else?

Have you recently changed the batteries? Mine won't remember it's settings and must be reprogrammed each time the batteries are removed.

Depending on which RCA model you have, the unit can be set to respond to either the "DSS" OR "AUX" input. You may want to check and see if you did this inadvertently by trying the "AUX" mode. If this works, you can set the unit back to "DSS" mode. Just a guess. I have one RCA unit like this, but my other two don't have this feature.
Sometimes the receiver also locks up. Try unplugging it for about 5 minutes to see if that fixes it.

Worst case - Best Buy sells RCA remotes cheap, but I'd recommend upgrading to the RCA RCU 810 universal learning remote -- $50.

Aaron - sorry, I didn't read your post closely enough. Thought you were saying it would no longer control the vcr and tv that you had just programmed, hence my battery change remark.

You can program your receiver to respond as SAT1 or SAT2 (DSS1 and DSS2 on older units) - this is to allow having two sets in the house without interfering with each other. If you have inadvertently set this to the wrong setting, the remote won't control it. I'm not at home to give specific directions on this right now, so check your manual.