The processor fan may become loud when the processor is under normal-to-heavy load (running such applications as Norton Anti-Virus scanner). This issue is likely to affect systems with BIOS version of 2CKT15A and earlier, with an Intel Pentium 4 Prescott processor installed.

Any of the following systems running Microsoft Windows 2000 or XP configured with an Intel Pentium 4 Prescott processor and system BIOS prior to 2CKT16A:

• ThinkCentre A50 (type 8084, 8085, 8126, 8147, 8148, 8149, 8174, 8175, 8176, 8177, 8178)
• ThinkCentre M50e (type 8179)

Update the system BIOS to version 2CKT16A or later.
 

Verify that airflow to the processor fan is not restricted by cables. Specifically, the IDE cable to the CD-ROM should be arranged such that the processor fan receives adequate airflow. If airflow to the processor fan is restricted, rearrange the cables to allow better cooling.