You can try SUPERAntiSpyware.
SUPERAntiSpyware is available as both a freeware and premium edition like Malwarebytes' Anti-Malware (see below), but the level of restrictions on the freeware edition are considerably higher.
The free version is limited to basic on-demand scanning and malware removal.
The premium version includes real-time scanning, registry protection, a scheduling service, auto-scan on startup, and 50 startup diagnostics to stop malware infections before they spread.
One of SUPERAntiSpyware's strongest selling points is its high level of compatibility with other protection tools like Avira, Kaspersky, Symantec, and McAfee. In most cases it can be run along side other tools without any conflict.