Outlook

To many mails in inbox? >50 = slow  

Having lots of large .pst files open, especially if any of them are on network shares (great way to lose data).

try running outlook in safe mode (outlook /safe) and see if it open faster.
if it is running faster you may have a problem with one or more of outlook add-on (plugin, like A/V etc.)

I think you have many emails in your account.

I'll recommend you to use the great third party recovery tool. It's a great utility and I believe it since I have used it. Please visit the site to know more about product http://www.petri.co.il/edbtopst.htm

1) Archive:
http://office.microsoft.com/en-au/outlook-help/archive-...
If there are too many emails it will take the emails out of the main inbox and place them into a second box called a PST which can allow the emails to be viewed later.

For data security maybe place the PST on a servers network drive for backup purposes.

2) Recreate the Outlook profile:
http://support.microsoft.com/kb/829918
May be a profile based issue. Recreating the profile resolves many outlook based issues.