I remember having this happen to me some time back. I still don't know why, but I booted into SafeMode and was able to do the System Restore. You might give that a try and see if it works for you.

Here is the skinny, Get yourself to the site raven suggested. If you are infected with System Check it is important that you do not delete any files from your Temp folder or use any temp file cleaners. This is because when the infection is installed it will delete shortcuts found in various locations and store backups of them in the %Temp%\smtmp folder. It does this so that you when try to launch a program from your start menu, none of your shortcuts will appear and thus making you think that your computer has a serious problem. Therefore, you do not want to delete any of the files in your Temp folder as it will remove the backups that we will use later in the guide to restore your Windows Start Menu. To make matters worse, recent variants of this family have been know to install the TDSS or ZeroAccess rootkits as well. These rootkits will attempt to stop you from using security programs that may help you to remove this infection. Good luck. Joe

When you use the link Bob provided be cool and follow along carefully, if you get flustered simply walk away for a while and return with a clear head and it will work great. You really need to have confidence in the anti virus installed on a computer, in this case McAfee. As long as it is up to date and allowed to scan daily you should be safe from a virus attack. Why would you click to download a second program? Does this Lenovo have any other protection besides McAfee? You might consider installing Superantispyware for protection from Trojans and the like. Be sure to click on the free version. Once installed look immediately for updates and run a full scan. This may take 45 minutes or more. Repeat that every one or 2 weeks to stay clean. Here is a link that might be useful: Superantispyware free

Then you will need to restore from a disc that came with the computer. Restore from Recovery Media 9 Insert the first recovery disk into your optical drive, then restart your computer. 10 Press "F12" as the computer begins to boot up and you see the initial BIOS screen. 11 Select "CD/DVD option" in the menu by using the arrow keys, the press the "Enter" key. 12 Click on "Recovery of Factory Default Software," then "Next." 13 Click on "Recover to out-of-box state," then click on "Next." 14 Click on "Next" to begin the restoration process. 15 Allow the Toshiba recovery program to work. This may take several minutes. 16 Press any key on the keyboard when prompted to do so to restart your restored Toshiba Satellite A135 laptop. Information taken from here: Read more: http://www.ehow.com/how_6772145_restore-toshiba-satellite-a135-laptop.html#ixzz2hcyDhiVP