If you're not technical, this is easier than it sounds, assuming you can get to a Run command or a command prompt (a "C: prompt"). On Windows XP, I did it by clicking Start, then Run... This brings up a little dialog box, in which you should paste "regsvr32 C:\WINDOWS\system32\jscript.dll" without the quotes and then hit the Enter key or click OK. This should do the trick.
If you still have problems, you may need to reinstall the latest Windows Service Pack or try some other tricks before doing this again.