Vista Business Startup Freezing

I've noticed that lately whenever I log onto my Vista Business OS, the desktop loads up and the startup icons begin filling the tray and then it will stop. The system will just sit there. I do have about 10 programs that load into the tray at startup. I defragged the drive right before it did this the first time. When I restarted the system it did this. Now, after I pushed the power button and powered it off (the system wouldn't let me sign off) and restarted it, it worked ok. I defragged again just to see what would happen and as soon as I restarted, it did it again. Could the defrag program have anything to do with this? What other problems could cause this? Is there a Vista diagnostic tool I can use for this to see what's going on? Thanks.

The defrag is configured to run automatically weekly. Could this defrag program have some quirk in it that would cause this to happen only after it runs?

Please post the information from this post: http://www.vistax64.com/crashes-debugging/282419-blue-screen-death-bsod-posting-instructions.html
Although you're not having BSOD's, the information from the reports will get us started

Hi,
hmm!! I doubt there might be a bad block on your hard disk, thats why every time you run disk defrag is works fine then stop again,, can you run a check disk > chckdsk /r > to see if it records any bad sector or bad block on the hard disk?

If not then do the following..
check your eventl logs for errors or warning.. might be helpful if you post that here..
Also on start > run > msconfig and go to the "startup" tabb and disable any unwanted programs to start when windows start. and Under the SERVICE TABB > select "Hide Windows application" and disable all the other services that you don't use, expect from "wireless/ battery sevices" ..This process make the computer starts faster as well..

What anti virus program are you running, this issue happens as well when you are running more than one antivirus program or none,

Run "ccleaner" to delete cookies etc
CCleaner - Free software downloads and software reviews - CNET Download.com

Run a Malware bytes scan
Malwarebytes Anti-Malware - Free software downloads and software reviews - CNET Download.com

Check the virtual and physical setting for the RAM/ memory.. If its wrongly set, set it as "system to decide"

Also check your windows updates..
cheers
Ash