Shipmate,
Confirm that you do not have an entry in your Services that says:
Superfetch|Maintains and improves system performance over time. Started|Automatic|Local System
It would be most unusual for it not to be there.
Concur with Bushfiva; do not re-install/restore point. Just leave.
Is your 4GB mem stick all devoted to Readyboost or do you have other files on there?