I don't know what Anti-Virus program you are using but I like ESET Nod32, used in combination with ZoneAlarm firewall. ESET is excellent with it's throughness, speed and flexibility.
Incidently, the lack of SATA drivers will most likely appear when you try to use a boot disk to reformat your HDD with third-party software if you have a SATA DVD/CD drive. An IDE CD/DVD drive, in my experience, should have no problems with booting partition software or WinXP installation when using an SATA HDD. I believe that I once used Paragon Partition Manager software--in Windows-- to reformat and partition the HDD (Of course it had to reboot into DOS to do the formating etc.), then just a plain (no added drivers) WinXP SP2 CD to install Windows XP Pro on an all SATA computer. So there are workarounds if you don't have the SATA drivers readily available.