Can't open tower to clean fan, removed 2 screws from behind the buttons and it still wouldn't come off.

Open the case, loosen the 2 screws holding the black plastic casingon the cooling tower over the CPU. Carefully remove, or tilt back to reveal cooling tower radiator and coil.
If there is a layer of dust built up (like there was on mine); carefully vacuum clean the radiator, cooling tower unit, fan and all other surrounding areas. Clean any residue from tower-to-CPU contact area.
Vacuum entire PC inside and out. Remove, reseat, vacuum video card. Reseat storage drive cables reseat the memory sticks, close it up and plug it back in start computer.

If your tower fan is like mine then in the handle there are two screws holding on the back just remove those and it comes apart.

There are two screws in the handle remove them and the back panel comes off if they are tower fans

You will need a phillips screwdriver (preferably 2 different sizes - some of the screws are tiny), q-tips and a can of wd-40.
On the back of the brookstone (the darker gray side) you will find 4 screws inside of 4 channels. Take these out.
Put the fan on its head. pry off the 5 rubber bases and set aside carefully so as they won't lose their stickiness. You will see 5 screws beneath these. Remove them and then remove the bottom plate. Now remove the 2 screws and washers, noting that the rounded side of the washer was facing you. Now pivot the base so that the 4 holes on the outer part of the base line up with the 4 screwsheads that are screwed into the tower. Take these out.
The 2 gray tower pieces should now separate easily. set the fan on a newspaper and blow away as much of the surface dust as your can. Now use your wd-40 (with a straw nozzle attached) and spray into the motor area where the actual fan turns. Also spray, from the top down, along the metal rod that connects the fan to the motor.
Now use the q tips, dipped into warm water, to clean the dust from the fan "blades" and to clean any other nooks and crannies you can see.
Lube the motor up one more time, put the machine back together and leave to dry out overnight.
Will work like a charm afterwards.

you have to remove the fan housing. it is usually screwed.

how do you disassemble it to be able to clean it

when you take all the screws out slide the back down. there is a screw at the bottom holding it from slideing the 9th screw so to speak. you have to take out the u shaped pin on the rod once that u shaped pin is out thats where you will find all the screws to the bracket holding the moter in place take all those out too. it seems like alot but it is really not.

first you have to remove the two plugs on top behind the buttons remove the two screws next you have to remove the base stand and their is one screw you have to remove then you can remove the front cover and you can get to the motor and fan.

On the backside of the fan at the botton is a little screw cover. Remove the cover then remove the screw. On the backside top of the fan right under the handle are two screws remove both of them. Gently pry the sides apart, about half way down on both sides are two molded clips, you can use a small flat blade screw driver to help seperate the cover.

cleaning the tower fan consists of this, i took the time to figure it out! unscrew top two screws on back of tower fan. then on bottom of tower fan is a screw cover,(pin size hole in middle of circle) pull cover off. unscrew hidden screw, and now with a little force it should pop right off. it exposes the filter and all it interior. front screen does not come off. oh yeah,your welcome!