Due to virus unable to logon on to system,
Needs to restore your windows vista to the manufacturing settings.
If you have not deleted the Recovery Partition then Turn of your computer and start your computer by "novo" key instead of power button.
which initiates OneKey recovery, and follow the on-screen dialogue. If your data is not important then you can delete all the partitions other then Recovery Partition, then follow the OneKey recovery process....
It doesn't matter how many partitions do you have or you have changed the partitions, as soon as you have not touched your recovery partition everything will work fine - with your OneKey recovery process.
Lenovo takes $45 - $50 OR1250 INR, India - for the recovery, if you don't have recovery partition.