1) Install Microsoft Security Essentials
2) Install MalwareBytes
3) Scan with TrendMicro HouseCall Online Scanner
4) Scan with Microsoft One Call Safety Scanner
Microsoft Security Essentials is a great Spyware/Malware/Virus scanner Free from Microsoft.
MalWareBytes will identify many Malware/Spyware software on your computer that other scanners are not able to detect.
TrendMicro HouseCall is a good Online Scanner that might be able to identify unwanted software the other scanners did not pick up.
Microsoft One Call Safety Scanner is also a good Online Scanner that might be able to identify unwanted software.
With all 4 products used to scan/clean your system, you should be in the clear.