CPU fan loud when PC goes into sleep mode

[Thunderstruk]

Windows 7 32bit AMD Athlon 64 X 2 Dual Core Processor 4000+ (Brisbane)

Every time I place the PC in sleep or hibernation mode, the CPU fan makes a loud noise because it starts spinning faster than usual. I have to unplug the power cable to stop the noise. This happens when i use the "sleep" button on the keyboard or when using the start button then clicking sleep or hibernate. I haven't installed any programs recently or made any changes to the system. It came out of nowhere. The CPU fan seems to work fine when the computer is running and CPU temperature is normal. There is no dust buildup on the fan or the CPU's heat sink. Any help would be appreciated.

 

[Ranger4]

How long do you allow it run with the fan running at high speed?. When the computer is put in sleep or hibernation mode certain files are rearranged & sent back to their location & the computer clears unwanted loaded files, so you may need to let it run a bit longer to see if it settles down.