I only gave my PC a very light cleaning by brushing dust off the fans with a small brush. Now it won't boot. What should I check first, and could I have accidentally loosened something or caused static damage?
4 Answers
Check the power cable at both ends, including the connection to the wall or power strip. Also verify that the switch on the back of the power supply is set to the on position. Those are easy things to overlook after moving the case.
Start with the simple possibilities: carefully reseat the RAM, check the power-button connector, inspect the PSU cables, and make sure nothing was knocked loose while brushing. A disconnected cable is much more likely than a component suddenly failing.
Make sure the computer was fully shut down before cleaning, with the power cable unplugged. You can then hold the power button for around 10 seconds to discharge residual power. Also consider whether the brush had metal parts or was intended for electronics, since an unsuitable brush can create static or accidentally contact components.
Inspect every cable methodically rather than just giving them a quick glance. Also, using an anti-static brush is important; a normal brush may generate static electricity. Even if the cleaning was minor, static or a slightly loosened connector could explain the problem.
The brush type is definitely worth checking. A brush without anti-static protection can be risky around exposed PC components.

I’ll go through the power connections and the PSU switch again. I may have disturbed a cable without noticing.