Find out if it's the speakers or the PC that's ginving problems. Simply try the speakers on another PC and/or other speakers om this PC.
If you're sure it's the PC, first check Device Manager if it notes any problems. And it won't harm at all to check the settings of the sound software. Something might have been switched to 'mute' by accident.
If none, undo the cleaning either by System Restore or by the undo options of your cleaning software, if those exist. That clearly depends on what you cleaned and how you cleaned it.
If yes, reinstall the drivers.
A repair install of Windows is the next step. A clean install of Windows comes after, and if even that doesnt help it's time to buy a new sound card.
I have a 5 year old Dell Inspiron 5150 laptop equiped with XP Professional. Attached to it is a small Cambridge Soundworks speaker system that has worked perfectly until now... Suddenly no more audio from this system, except for the computer inside speakers that is working just fine. I have checked all the connections (speakers and woofer). I have been doing a lot of "cleaning" lately - due to the fact that my computer has been very slow... I used CCleaner, WinUtilities and Premium Booster. My anti virus is AVG.
Please help... I miss my music!