I have a Lenovo Thinkcentre desktop computer. When I power the computer on it doesn't send a signal to the screen and it makes a horrible screeching noise. It is not the fans or the speaker.

SOURCE: Monitor makes loud screeching vacuum sound; no screen display..?

check to make sure that there arent any magnets near or around it

SOURCE: my dryer makes a horrible screeching noise while

It sounds like your belt needs to be replaced. You're smelling the melting (burning) rubber.

SOURCE: i have a problem in Lenovo/IBM ThinkCentre A51

open case and see if the fan is dirty, clean it with canned air if that solves the problem your set. If it doesnt solve your problem then the Fan will have to be replaced ,in order to keep the cpu cool.

SOURCE: IBM ThinkCentre A51 PC Desktop won't boot

This could still possibly be a bad power supply, even if the fans and drives spin up. If you have a spare try hooking it up.

the list of things that can cause this are:

bad power supply
bad ram
IDE error (optical or hard drive problem)
bad card (modem, video card etc.)
bad processor
bad board

The first thing i would look for in this case is blown capacitors. Those are the little things on the board that look like little soup cans, usually with silver tops. If the tops of any of them are bulging or have junk leaking out of them, you have a bad board. If you are handy with a soldering iron you can try to replace them. Not sure if radio shack still sells caps, but they are easy to find on line. I have about an %80 success rate fixing boards in this way.

If the PS change doesn't work, then try it with different sticks of RAM, if you have more than one, pulling one at a time until it starts or you've tried it with all the ram. If not ram, disconnect the ide cables from the board, these are the wide ones usually connected to the HD's and optical drives. If it still doesnt start then pull all the cards. If it doesnt start then, try swapping processor and if still no joy a new board.

SOURCE: why does my Dyson animal

I can't probably help you but I can tell you what Dyson told me. I have this same vacuum and it just started making that same noise. When I called their rep they had me take off the bottom plastic piece (comes off real easy by taking a coin and turning the three circles). Check to make sure the belt isn't broke. Then, they had me pull toward me the roller brush and turn it to get it seperated from the belt. Then, take off the belt. On mine, the spindle was full of dog hair clogging it. I took twizers and narrow pliers and pulled everything off. Then put it back together. It worked fine for the next few times I vacuumed then it started again. So, I did the same thing again and found this spindle covered with the hair again. Cleaned it, put it back together and it worked again. Today, while vacuuming I picked up a piece of string and that noised started again. Turned it over and saw that string on that spindle. Took it off, cleaned it and it worked again then started the screeching again. So, tomorrow I am calling a vacuum repair place. IF you have the same vacuum (which you do) it should still be under warranty. Dyson told me I would have nothing to pay unless I abused the vacuum which I did not. Hopefully I am not without it very long...I have two golden retrievers who do shed alot.