weird problem with "freezing"

hello
there is this really annoying problem i have

from time to time my windows 7 32 bit freezes .. :)
but this ONLY happens ( from what i have noticed ) when i open something

examples :
if i go to the add/remove sometimes it does not want to load the programs list and explorer "kind of crashes" . i cant do much except patiently wait and try and click the X or click a lot until it asks me if i want to restart the program , wait for it or to close it
during that "freezing" period i cant do much event ctrl + alt + delete takes a while to actually open and if i try ctrl + shift + esc ( task manager ) it dont open untill i close the add/remove window or stop it from loading all programs and qickly close the window

the second example ( and most annoying ) happens on windows live messenger ( any version )
i chat with someone , open the window , close it .. works fine
but then there is this .. there is ONLY 1 person that i cant open or close a chat window with .. i can chat with her but she has to write first ........ if i open the chat window msn freezes , everything works if its already opened ( youtube , winamp , chrome , etc etc etc ) .. but if i try to run something , or save some document i cant do that and MUST open task manager ( via ctrl alt del ) and close msnmsgr.exe (which always uses about 70-80k memory ) and then everything is back to normal until i open msn again and do the same mistake or press esc ( to close the chat window ) in a rush and " HERE WE GO AGAIN ...... "

help ?
any more info you need ?

tnx for replying
i did as it was writen in the guide
disabled all , enabled all .. experimented and so far i got to this
avast is always turned on , even after disabling it from services and from startup
i left cyberlink brs to start from the startup items and disabled everything else
still freezes , even with cyberlink brs disabled .. i was very patient when opening add/remove function .. and it loaded but everything i wanted to open had to wait untill the programs got loaded . tried the second option .. opened chat .. freeze , end process = no freeze .. -.-

what now ?
i dont want to try the last step .. microsoft services .. i read it can affect the PC in a bad way
dont suggest format , thats not an option at this moment


EDIT :
i forgot to mention this
i got a new grafic card , GT 240 1 gig
had GTX 9800 , had problems with it and posted here on the forum
i installed newest drivers for gt 240 and did a clean install ( setup deleted old files , installes new ) ... and after restart my P5K motherboard loading screen shows up as normal then something something shows up again normal and then AGAIN the same screen from my motherboard shows up and it never did that before , i think when i started the PC after i got it from the shop it didnt show that screen and after drivers install it did

i dont remember but i think i installed the drivers once , then i did something and tried reinstalling the drivers .. i think there were some problems .. not sure

disable my anti virus ? how and why ?
oh yea i remember now
i had Avira and i deleted it because it caused problems , and i believe it froze the PC

ok
HUGE PROBLEM :) ....

i removed avast , everything worked fine
so i decided to install system mechanic 10
but i didnt install anti virus and anti malware with it so i removed it and installed it again so i had to restart the pc

so now i try to boot .. no hard disk found -.- .... **** ..
i booted once only to desktop and then hard disk started making this weird noise .. something like a record player CD running and running after the song is finished
now what i do ? -.-

i go in BIOS .. no sata boot disks found

EDIT : i opened case to check if maybe some of the cables isnt attached or something like that ... still same problem :@ :@

my computer wont start without a boot device
i am writing from my laptop


and what u meant tune up , mechanics stuff ? like removing the sata cable and power from the hdd and plugging it back in ? or software related as in BIOS ?
if its the first thing .. already done
second thing never touched it , never will