System Restore automatically monitors and records key system changes only.


Restored
Registry
Profiles (local only—roaming user profiles not impacted by restore)
COM+ DB
WFP.dll cache
WMI DB
IIS Metabase
Files with extensions listed in the <include> portion of the Monitored File Extensions list in the System Restore section of the Platform SDK

Not Restored
DRM settings
SAM hives (does not restore passwords)
WPA settings (Windows authentication information is not restored)
Specific directories/files listed in the Monitored File Extensions list in the System Restore section of the Platform SDK
Any file with an extension not listed as <included> in the Monitored File Extensions list in the System Restore section of the Platform SDK
Items listed in both Filesnottobackup and KeysnottoRestore (hklm->system->controlset001->control->backuprestore->filesnottobackup and keysnottorestore)
User-created data stored in the user profile
Contents of redirected folders



Read up on system restore here--> link