I have two Dell computers at home. Every time I put them to sleep mode, the fans turn off except for the other one, a Dell OptiPlex GX200 with a Phoenix ver. A05 BIOS. I’ve tried searching the net about this odd behavior on my computer, and finally came up with information related to this matter. In the article that I found, it says my computer needs an ACPI enabled system which is set to S3, for the fans to be disabled during sleep mode. I’ve checked the BIOS setup and wasn’t able to find anything about ACPI, S3 or power management. I’m asking everyone to help me in this problem of mine. Help is deeply appreciated.