I have on the very odd occasion used a vacuum cleaner with extreme care. Not done any harm to my machines, and it runs out far cheaper than perhaps using compressed air cans.

Some of the £shops seem to stock computer cleaning aids,and other computer accessories, perhaps worth a look there?.

static can form around the plastic nozzle due to the flow of air so do not let the nozzle touch anything.

Whwn cleaning PC innards I use a hair dryer on cool low blow to shift the dirt and a small paint brush and a ladies nail dodah to scrape the fan blades an heatsinks clean witth all the gunk at the bottom of the machine finish off with a vac to get it out.

*Laptops require a different regime I do not recommend blowing anything into the vents *

a vac against the input grills may clear some of the dust and fluff

as yours is overheating and fan rattling I think you will need to open it up and scrape the fan blades and heat sinks clear off gunk. and use the vac to lift out the gunk

I always use compressed gas tins for computer cleaning but, always scour eBay to get them as cheaply as possible, usually around four at a time.

I find those free wooden sticks you get to stir your drink with at Coffee Shops are just the thing. I usually grab several when I buy my cuppa at Railway station.

I have a compressor in the garage which I use. BUT, stop any fans turning - if not, they act as generators and can blow sensitive components through over voltage.