One needs to be cautious when cleaning as you just found out. Its not too difficult to induce a static charge if using a vacuumn cleaner brush or something similar so those become no-no's. In your case, you mentioned you were having problems previously but didn't elaborate. A steady beep or a continous series of beeps both include motherboard as a potential culprit but before you run out to replace yours, lets get back to a couple of basics. Unplug your computer from the wall or whatever outlet its connected to. Pull your memory and clean it with a soft pencil eraser by wiping down, not across the contacts. Then clean it with a QTip dipped in alcohol, make sure it hets dried and then re-insert it. You can also do the same for your video card. Next, disconnect each IDE cable lead one at a time and re-insert it firmly. Sometimes oxidation will build up and this may help to provide a better contact. Check your ATX power connector at the motherboard and your 4 pin 12 V connector if you have one. Now, check all of your molex connectors. Now, you can plug it back in and try starting up again. If no go, clear CMOS. Disconnect power, open the case again, disconnect the ATX power header from the motherboard. Move the CMOS jumper from 1&2 to 2&3, wait 10-15 seconds, re-jumper 1&2, reconnect the ATX power header, plug your computer back in and try to start and tap on the delete key to get into BIOS setup. If successful, set at default and F-10 your way out.Beep Codes Here.
Good Luck - let us know what happens.