Re: Inspiron 1545 - Random clicking/popping noises
Try listening through headphones, perhaps in another room away from the computer or with a blanket over the computer to muffle the sound. If you can't hear it in the headphones then it is probably not an audio problem.
Hard drives can make clicking noises for a variety of reasons, including failure but even healthy ones do. You might try running diagnostics on the hard drive. To run diagnostics restart the computer and as soon as it starts to boot up hold down f12. Select 'Diagnostic' from the boot menu. The computer will run its pre-boot assessment tests (PSA) first. The PSA tests include a brief hard drive test.
After the PSA tests finish Dell Diagnostics tests will open. Select 'custom', then the hard drive test. [If you wiped the Diagnostic partition from your hard drive when you reformatted then the Diagnostics won't appear as an option.] Be on the lookout for degrading performance and/or slower boot up times as signs of a failing hd.
I don't know what Dell will do. They only support the OS that the computer was shipped with so it is possible that you might have to reinstall Vista to get service ... I'm not sure.