Any system will start to drag over a period of time when new startups are seen and the uninstallers tend to leave items behind in the system registry still trying to load drivers and start up things no longder on the system. If you copy, create, move, delete large volumes of files a drive can get fragmented at times too with the simple need of maintainence.
The loss of being able to use the system restore feature however is something that may end up seeing a repair install of Windows if not being able to be repaired easily. When IE windows shut randomly that could be from a need to reinstall the drivers for the connection again to see those refreshed depending on how you are connecting online.