HDD led only responds to CD-ROM access

[chobibo]

I cleaned my pc earlier today, I disassembled it and assembled it after I cleaned its parts. I noticed that my HDD led only responds to CD-Rom access only, but before I cleaned it it was working fine, Also I used the motherboard manual to re-assemble the pc. Can you guys tell me any possible reasons why its acting like so. My motherboard is an Asrock 845GV with 2 HDD and a single CD-ROM set to master slave.

 

[Prometheus]

Two things.
1. The power was off when you cleaned the computer, right?
2. Are you 100% sure that everything is pluged in completely?