system restore virus

how do i delete all the viruses on system restore cuz i scan my friends comp last night there's like 400 viruses mostly from system restore?...

Thanks:

 

Clear past system restore points and create a new one.
Right click My Computer and select Properties. On the System Restore tab, check the box to turn System Restore off. Click Apply. Now, uncheck the box and click Apply. Click OK, then OK to close the System Properties dialog.

Verify a new restore point was created.
Click Start>All Programs>Accessories>System Tools>System Restore
Select 'Restore my computer to an earlier time', then click next.
You should have a newly created System Checkpoint available. If so, click Cancel. If not, click Back and select 'Create a restore point' then click Next. Give the restore point a name and click next.