Admittedly, I'm not as skilled on PCs as I am on Macs, but here's a series of quick tutorials from Microsoft.

Each PC should have Windows Movie Maker. If it doesn't, download Movie Maker from Download.com.

Movie Maker is an easy to use, drag and drop video editing program.

1. Click "Start" and locate Windows Movie Maker. Open it.
2. Once it's open, look on the left-hand side and click "Import Videos."
3. Find the appropriate file and click import.
4. In the top window, you should have several clips.
5. Click on whatever clip you want and drag it down to the bottom timeline.
6. Repeat, organizing your movie in the order you want it to appear.
7. Clicking on "Edit movie" gives you several options.
8. Choose "Make titles or credits"
9. Choose where you want to add the title. Add it.
10. Follow the same steps as 7-9, but add credits instead.
11. You can import music by clicking on the "import music" on the left-hand column.
12. Drag and drop the song onto whatever clips you want it to play at.
13. Once you're done editing, go to "Finish Movie" and decide whether you want to save it to a disc, or whether you want to send it to YouTube.

Here's a how-to video