Last Updated Nov 4, 2009 9:25 PM EST
Most versions of Windows 7 have the ability to create a System Repair Disc that boots into a simplified repair environment. There, you can use System Restore to return your PC to an earlier restore point, or you can run a number of repair and diagnostic tools.
But to reiterate: If you wait until you have a problem, it's too late. Make a System Repair Disc today.
It's simple -- click Start and then type "repair" in the search box. Then click Create a System Repair Disc. Insert a recordable CD or DVD and create a disc. Label it and put it somewhere safe, in case you ever need it.
And don't panic. Most problems are surprisingly easy to solve -- check out Rick's Three Was to Deal with Sudden Computer Glitches.