The free version of AVG anti spyware is similar to SpyBot or AdAware, it does not do real-time monitoring, so it shouldn't be a problem. It is generally a good idea to have an antivirus product and at least one separate anti spyware product at the same time (I have two). There is no single anti spyware product out there that will actually catch everything you can get on your computer, so doubling up can keep your system very clean.