is there an un-do feature on your anti-spyware program?
if not, try a system restore
To use system restore: Through Help and Support:
1.Click Start, and then click Help and Support.
2.Under Pick a Task, click Undo changes to your computer with System Restore.
3.Follow the instructions on the wizard.
Through the All Programs menu:
1.Click Start.
2.Point to All Programs.
3.Point to Accessories.
4.Point to System Tools.
5.Click System Restore.
6.Follow the instructions on the wizard.