Instead of running repair, completely uninstall the client tools using setup, and then reinstall them from scratch. Make sure you also uninstall any add-ins or plug-ins that you're currently using in SSMS. Once you've installed SSMS from the media, then apply SQL Server 2008 R2 Service Pack 1. If you have Visual Studio 2010 also installed on your machine, make sure you've installed service pack 1 there before re-installing client tools.

FWIW, I've found the new features and enhancements in SQL Server 2012's version of Management Studio to be very beneficial, and have been using it as my only SSMS version since the early betas to manage 2005, 2008, 2008 R2 and 2012 instances with no problems. RC0 is out so it may be worth trying that version too. It's a big download for just the client tools, but worth it IMHO. You can get it here:

http://www.microsoft.com/download/en/details.aspx?id=28145

SQL Server Management Studio Startup

When Microsoft's SQL Server Management Studio (SSMS) starts it tries to connect the Certificate Revocation List (CRL) of Microsoft:

http://crl.microsoft.com/pki/crl/products/MicrosoftRootAuthority.crl

The underlying .NET components of SSMS are trying to contact the Certificate Revocation List and SSMS is unable to do so. This slows down the overall loading procedure. (15 seconds per certificate apparently)

Ok so here is what is happening. SSMS has a high percentage of managed code, all of this code is signed when we ship it. At start up (if this setting is checked) the .Net Runtime tries to contact crl.microsoft.com to ensure that the cert is valid(there were some fake certs issued in Microsoft’s name a while back so this is a very valid concern). If there is no internet connection or there is a problem contacting the certificate revocation list server then this will delay SSMS startup.

Reference: FAQ, Why does SSMS take 45s to start up? (MSDN Blog)

One issue that can cause this problem is that if the server does not have access to the internet, then the .NET framework can’t access the crl.microsoft.com website to verify that the digital signatures used to sign the binaries for managed applications are valid. Each certificate check has a 15 second timeout in the .NET runtime implementation. Depending on what features are installed, this can add up to a minute of startup time for Management Studio.

Reference: SQL Server Management Studio Startup Time (MSDN Blog)

Solutions

You can circumvent part of the issue, by downloading the certificate directly be entering the link into your browser and then importing the certificate to your certificate database

• OR -

You can reconfigure your (company's) firewall to allow connections to Microsoft's CRL

• OR -

You can reconfigure your personal antivirus/firewall to allow connections to the Microsoft CRL

• OR -

You can configure your (company's) firewall to send a timeout faster to your client for requests accessing Microsoft's CRL.

• OR -

You can configure IE to no longer "Check publisher's certificate revocation" in the advanced settings.

(See above mentioned blogs 1 and 2 for details)