I have a Compaq Presario SR2180NX desktop. Throughout it's use, the FAN (Both processor and case fan) went SUPER loud, then back to quiet. This repeated all the time.

I cleaned the case out, and removed all the dust, but the *censored* fans are still doing the same thing. Now, the fans are one loud permanently and it's really REALLY irritating me.

I even have a third fan in the case, and the side panel is off! None of the suggestions I saw helped.

Is it fixable or should I start looking for another computer?Its probably your cpu fan MAKING the NOISE.  Your cpu is getting hot and the fan needs to speed up to cool it off.  Nothing you can do bedsides get a new cooler or GIVE it to me.90% of all fans in a PC can be replaced including your CPU fan...
I would do this immediately if you want to save that machine.
Using it as is can result in PERMANENT damagem
Remove the CPU fan and one case fan and bring them with you to get a proper match...

P.S. Also pick up a CMOS battery while you are there...it may not be retaining the default settings which is throttling the fans to full.
Part # CR 2032 about 3 bucks.

You'll probably rescue that machine for under 20 Bucks. Take your time and pay attention.