CPU fan stock running hot

I have a ASUS Essentio - CG5275-AR003 - 8 GB RAM - 3.2 GHz - 1 TB HDD had it for about 2 or 3 years or so got it from best buy. Got some upgrades for gaming like 800w fan evaga graphic card. got some software that let me see the tempture of the computer for some reason my heatsink is doing about 80c to 90c just being idle and turning it on. I seen some other asus computers had the same issue of the heatsink being way to hot or saying the program itself is wrong showing the wrong tempture. I say that stock heat sink itself is to crappy for the I5 cpu itself. Is it possible that the stock fan for the asus computer itself could have been a better one then the one it has now. all my other compentents are running at 30c idle. My graphic card i have to tweak the setting is to high. My computer has been worked on by best 3 times allready for other things. like it takes 5 to 10 mins to shut down they dont know why . they replace my windows 7 with another copy the one i had itself was corrputeded. then then my hard drive failed on me they dont know why. I say my computer been a lemon from day one just never gaved up on it or got a new. I went to bestbuy and asked why my computer is running so hot around 80 to 90c. the answer i got was my heatsink is dusty is good enough for a stock model and just reply thermal paste.

1. I say the stock fan model sucks for the asus computer for the I5 need a better upgrade or model it doesnt do the job right.
2. its been running this hot to began with i just noticed the software that telling me this dont know if the programming is wrong or the setting is set wrong again best buy didnt see this problem that my heatsink is at 90c while the rest is at 30c.
3. MY hard drive got replaced they dont know why only have it for 2 to 3 years it takes about 5 to 8 mins before the computer can shut down.
4. The most annoying part when i asked if i wanted to upgrade my heatsink to a better one they really didnt want me to upgrade to a better one and that the stock model is good enough. Wow just add more themial paste if my computer was running this hot before and i just add themial paste it gonna be like 3 more months before i just keep aeding more to it the heatsink is running way to hot.

The main thing is i wanted to know is anybody that owns a asus is having the same problem with the stock heatsink giving out way to much heat for being idle and not doing aything. The asus i got i cant change the setting on the fan speed or the tempture on my computer.some of the asus come with programes like the AI probe. or some graphics cards com with some like you can customes them like the anetic.

I was wondering if there any graphics programes i can download i have the evaga one but it doesnt do much like the other ones i seen with more options. The heatsink im getting is pretty big and should laste me a long time is the nactuo n-14. this way i dont have to upgrade for awhile. i need bestbuy to figure out my the tempture on my heatsink is to hot and prove that it destroyed my harddrive. yes i know this is pretty long just kinda annoyed or been in the same spot trying to get some anwsers some feed back be cool or any ideas. I just starded to play some mmo online games and not going for the high profile memory because at the moment dont know which ones to get and the prices on it just for 16gb is the most i can put in because of the heatsink size abd the location of it. The program i go tnow is fanspeed that lets me see all the rpms and is showing that my heatsink is doing nothing but the fan is running and for what i know it been like this the whole time.