i would remove the personal folder from outlook in the profile. then run a pst cleaner. outlook gets funny with pst files after they reach over 1 gig in size. you can use scan pst to try and recover the pst file, and then add it back to the profile.
you can also try creating a new profile. it wil redownload all the messages currently in your inbox. either way you will still want to run scanpst to check that personal folder.
you can get scanpst from
http://www.emailaddressmanager.com/outlook/Scanpst.exe.
save the file to 'C:\Program Files\Common Files\System\MSMAPI\1033' and you can just go to start, run, and type in scanpst.exe
lastly you can try running outlook in safe mode. go to start run and then type in outlook.exe /safe