help! Ticking computer when connected to AC

[xsimixx]

Hello, I need some help,
today i just opened the back of my mom's laptop (acer aspire5670) and closed it again without touching anything.
Then I connected the battery and AC and turned it on tho check if it still worked and I noticed a new ticking sound, like to marbles bouncing. So I turned it off again and it kept ticking even if it was completely shut off. It stopped when I unplugged the AC (battery still inside).
I tried a second time and had the same results.
It starts ticking after couple seconds even just by connecting the ac while pc is off.

So I reopened it and tried to figure out where it was coming from, but couldn't see anything. I just dont think it was the HD, the sound wasn't coming from there.

Can it be that its caused by some dust?
What should I do?!

thanks in advanced

Simon

 

[jackson1420]

Put your hand on the HDD physically and see if you feel anything when it makes those noises.

Ensure all wires aren't touching any fans. Check the sound isn't coming from the PSU by putting your ear up to the source.

Your HDD is the only component with moving objects besides your fans.