Windows System restore is a useful tool that reverts your system to a previous state in case of virus attack or system crash.
Though this tool is useful, you can disable it to increase system performance especially if you have minimal hardware to run Vista.
This can help increase the performance of your system. To do so, open the Control Panel and double-click the "System" icon.
Click the "System Protection" link on the left pane. Clear the checkboxes next to the corresponding drives and click "OK".