Pairing an antivirus with a firewall can be tricky since many of the same features are included in both. Sometimes certain combos will work fine on some system while other systems you can run into all kinds of problems.
Windows default firewall will work with any AV, so you will not have to worry about compatibility issues.
The most simple way to avoid problems is to use a security suite AV + Firewall already included to be compatible.
Freeware security suite options include:
1. Comodo Internet Security (very powerful but requires constant maintenance and tweaking)
2. ZoneAlarm Free Antivirus + Firewall (uses Kaspersky AV engine, excellent download protection)
3. Outpost Security Suite FREE (uses VirusBuster and Agnitum AV engines)
4. Roboscan Internet Security Free (uses BitDefender and Tera AV engines)
5. FortiClient Security Standard (has excellent zero-day malware protection)
Enjoy!!