I too use a compressor. Easily gets to places a paintbrush wont reach with no disassembly required. Mine was also bought for paint spraying for about £50 off ebay. Perfect for the PC. If you're going to consider buying a compressor just for PC cleaning you can get a simple air blow gun attachment for about a fiver rather than wasting money on a paint spray gun you don't need. They can be a little violent at 7-odd bar so you might want to turn the compressor down a little or just keep your distance from delicate parts 