You might want to sum up all your issues & how/ when they started.
System Restore issues are often virus & or malware issues.
You could try starting the service in safe mode. Here are other tips specific to System Restore:
http://www.google.com/search?hl=en&q...=Google+Search
http://bertk.mvps.org/html/srfail.html
The symptoms of your DVD/CD drive is also a common symptom with many possible sources including viruses & or malware. Especially with "an error trying to disable one of the drives."
If this error is repeated please post the error message verbatim.
The 998 error is possibly indicating that the registry has
lost rstrui.exe
What happens when you:
Start/Run/ %systemroot%\system32\restore\rstrui.exe
What about your anti-virus & firewall?
Have you made any hardware & or software changes etc.?
You also might want to go ahead & run a HijackThis log thru that section:
Please follow the instructions
HERE & then post your log in a new thread in the
Spyware, Adware, Viruses and HijackThis Logs section.
(
Not in this section please).