AntiHook is a program designed to act as both an anti virus and rootkit detector in one. The protection system works in real-time so it follows a "prevention is better than cure" approach to tackling viruses and rootkits.
One thing I particularly liked about this program is that no updates are required. With most anti-virus programs, they're always kicking into action to update when you least need it. The developers say that AntiHook utilises "advanced behaviour-based technology" so no ongoing data definition updates or high subscription fees apply here.
Another welcome feature of this product is that it's one of the few anti virus programs that does not conflict with other security programs. However, that's no guarantee that it won't clash with yours since there are literally hundreds of solutions out there but the fact is that this program works discreetly and does not consume many resources.
If you don't want to install a separate anti-virus and rootkit detector, this is a lightweight and sicreet solution although you may find that it does tend to miss certain pieces of adware and malware.