Here is a Computer Secret that I use just once in awhile - but it's a Biggy:
System Restore - the best thing Microsoft ever did for their customers. This will save you tremendous hours of heartache by re-setting whatever FREAK thing happened to your computer.
I am a power user; I know what I am doing, and still I have to do a System Restore about every two months. Unexplainable things happen, this is how to fix them:
Windows XP Users:
1.click Start
2.All Programs
3.Accessories
4.System Tools
5.System Restore
6.Click Next
Window's Vista Users:
1. Just type Restore into the Start menu search box, and you'll immediately see System Restore at the top of the start menu
The dates in Bold are the most recent restore points which automatically set each time you shutdown. (Another good reason to do a system shutdown nightly.)
1.Choose a date very near to the time you discovered the problem.
2.Click Next
3.Read the screen, click Next, and trust it. It should all be fine.
If the problem still persists, choose another date slightly further back.
(You can go back two months but I don't recommend that. Inch your way back a bold-date at a time until the problem is fixed.)
Warning: Sometimes System Restore doesn't fix the problem. At that point, you will have to fix it by trial and error. Of all the times I've used it, it has worked 98% of the time.