(I'm totally new to video editing so sorry if this is a dumb question)

I'm just trying out effects and the effects stack says they're on the clip, but the video doesn't change at all. I got the mirror one to work for a second but when I changed it, none of them worked anymore, including when I put mirror back on.

Colonel, it is not a dumb question, but we need more information. "none of them worked anymore" is a quite useless description of an error.

Which version of kdenlive? Which effects did you try without success? What did you do in detail? What did you change here: "...when I changed it..."?

If you think it will help us: Sometimes a screenshot says more than 1000 words.

It's version 4.4.5. What I meant by "when I changed it, none of them worked anymore" was I took off mirror and put on other effects, but no effects would change the clip after that. Mirror also didn't work anymore when I put it back on. I tried grayscale, pitch shift, pitch scale, mirror, dust, and I think speed, and maybe some others.

http://s15.postimage.org/ucv2pargr/Screenshot_1.png

4.4.5 is not the version of kdenlive, because the actual version is 0.9.3.
4.4.5 might be the version of KDE (The desktop enviroment)

It's working now so oh well.

colonel sanders - from your screen shot it looks like you are running kdenlive in Windows. Is this true? How do you do that? Virtual Linux box or something ?

Action is necessary to look at the effect of the Project Monitor, and judging by the screenshot you turn on the Clip Monitor
http://userbase.kde.org/Kdenlive/Manual/Monitors