Computer "knocking" help

[FVtreas]

We have a three year old Dell tower that has suddenly developed a knocking sound? Periodically (every 3 or 4 minutes or so). We hear 3 or 4 knocks coming from the tower. Any help?

[LuckySevens]

Open it up and let the little mouse out. He He...Sorry folks, just a little humor today.

[Indydealmaker]

We have a three year old Dell tower that has suddenly developed a knocking sound? Periodically (every 3 or 4 minutes or so). We hear 3 or 4 knocks coming from the tower. Any help?

I heard something similar earlier this year. It was not long that my hard drive died. Better do a back up now.

I know of only one other moving part, the cooling fan. That is not critical (although you do need a good working fan) and easy and cheap to replace.