System restore will not recover cookies, browser history and cache. Nor will it restore files. System restore restores registry settings associated with the OS and other programs and will reverse installations and uninstallations provided the files are still on the computer. System restore won't work if the files in question are gone.
As for files, if the deleted files are in the Recycle Bin, you can move them out of the recycle bin into another folder in order to look at them. If they aren't in there, you'd need some kind of recovery program and the success of using it depends entirely on how little the disk has been used. In other words, if you need to recover something you deleted, don't use the disk for anything.
Help us help you. If HelpBot replies, you MUST follow step 1 in its reply so we know you need help.
An ounce of prevention is worth a pound of cure
SpywareBlaster, WinPatrol Plus, ESET Internet Security, NoScript Firefox ext.