Dell Dimension 9150 Booting problem - HELP!

[danboy34]

Not sure if this is the right area to put this but new to this forum.

I recently bought a second hand Dell Dimension 9150 (not even two weeks ago). It all seemed to be working fine and not had any problems. Tonight I turned it off as normal but when I went to turn it on an hour or so later, it kept making a weird buzzing/"burr" sound repeatedly. Nothing was showing up on the monitor even though it was on. Most of the lights turned on as normal and flashed to indicate they were working but some of the other lights are staying on. These are numbers 1 and 3, or 3 and 4.

I checked the official Dell website on another computer and I kept getting lights 3 and 4 stuck on at first but now it seems to be lights 1 and 3. Both of which are apparently memory problems according to their site.

I did manage to turn it on once but it shut itself off after a few minutes use. It also seems to fail as it starts up as when I push the power button it goes to start, stops for a few second and then goes which it never used to.
I'm not a very technical person so I don't understand why the memory suddely has problems or what I could do to solve it??

Any help would be greatly appreciated

[lectrocrew]

Most of the lights turned on as normal and flashed to indicate they were working but some of the other lights are staying on. These are numbers 1 and 3, or 3 and 4.

I checked the official Dell website on another computer and I kept getting lights 3 and 4 stuck on at first but now it seems to be lights 1 and 3. Both of which are apparently memory problems according to their site.

If you have two or more memory modules installed, power down and take precautions concerning grounding yourself to the case before touching any internal components, remove the modules, reinstall one module, and then restart the computer. If the computer starts normally, power down and take precautions concerning grounding yourself to the case before touching any internal component, then reinstall an additional module. Continue until you have identified a faulty module or reinstalled all modules without error.
Did I mention be sure to disconnect power and take precautions concerning grounding yourself to the case before touching any internal component?