Had to disable heuristics to all, and exclude shellcode injections for some


I had to disable heuristics and exclude for example FireFox 4 from shellcode injections because when I was opening some webpages my browser freezed “to death”. Also Metatrader4 application could not started when those functions were on. I have also switched off all cloud-computing related options in Antivirus and Defense+.
Now, when I browse my folders on HDD I can enjoy normal speed, and applications run correctly.

I have AMD Turion 1,8Ghz, 1 GB RAM, 5400rpm Seagate hdd, XP SP3. I have found CIS too heavy with its default settings.
Question is: Are those settings now safe??? Especially - is adding FF4 to injections exclusions safe?

I must admit - have had NOD32 installed once, but i got infection, so went through tests and have found nod32 is kind of weak

I know that no security suite is 100% guarantee, but for my setup CIS is too heavy on resources, I know it is free, but still.

Assuming you downloaded FF4 from a reputable source, and therefor is the real program there is no problem because FF is not trying to exploit the apparent buffer overflow.

Thank You for the response.