**Edited from the post that was deleted.ME is an old operating system and as such all it's problems are well documented. Some of us here have run the operating system from day one and either had the problems personally, or seen the issues through this and other forums, and, or, seen the problems through running small computer tech businesses in daily life.
You are right to not do something you aren't sure of, or confident in doing, as that usually leads to errors.
But, having said that, everyone has to start somewhere and a few of us here started on this (and other) computing.net forums.
1) So keep system restore running for the time being till you're convinced it's more hassle than it's worth. In which case you are going to have to fix it.
2) Missing or corrupt .htc files are nothing new and can cause numerous other errors, just means the file wasn't created or it's corrupt. More information on what they are, what they do, can be found at the MSDN library:
http://msdn2.microsoft.com/en-us/li...
3) Regarding editing the registry to fix the problem, if you look near the bottom of MS Article 275646 it gives you an easy way round to do things...
Look at the grey box with text in it, starting with the word REGEDIT4 and copy all the text in the box, starting with the word REGEDIT4 and ending in x-component"
Open Notepad (not Wordpad) and paste the text into it. Save it as SR_Merge.reg
.reg is the important bit, means it's saved as a registry file and Windows knows what to do with it. SR_Merge just means "system restore merge" you can name it anything you like.
The important thing here is to back up the registry. Easy enough. Go to Start >> Run >> and type scanreg or scanregw and click OK.
When you receive a prompt to back up the registry, click Yes. And when you receive the "Backup complete" message, click OK.
Now double click on the SR_Merge.reg file you created and follow the prompts through accepting the changes it's going to make.
Reboot the machine and the Saturday, Dec. 30, 1899 error message box should be gone.
...and if it doesn't work, or something bad happens, you have a good registry configuration you've saved to go back to.