Some apple apps on my MBP just disappeared?!

[dryJ]

Last Thursday, i shut my MBP down and gave it to a friend to look after while I went on a driving lesson, OS X has a password so he couldn't have got in, but when i turned it back on that afternoon, some of my apps were missing, such as Address Book, iCal, iChat, iSync, Safari and a few others I still haven't noticed. I have been able to re-install the apps, but why did it happen in the first place?!?!

Early '08 Macbook Pro 2.5GHz version

Any help much appreciated.

EDIT: I haven't been able to re-install iSync, it isn't available on Apple's website for download, and other sites want me to pay. It isn't a re-install option when i put the Mac OS X Install Disc 1 in. Any help in re-installing iSync would be very helpful.

 

[WildCowboy]

Use Pacifist to grab iSync off of the install disc.

I have no idea what could have triggered the apps to disappear other than someone gaining access to the system and deleting them. They don't just disappear.

 

[dryJ]

Use Pacifist to grab iSync off of the install disc.

Excellent, this has worked a treat, and I have now got a list of all applications that got removed:

Calculator
Chess
Dictionary
Font Book
Front Row
Image Capture
iSync
Photo Booth
Preview
Stickies
Safari
iCal
Address Book
iChat

I have been able to reinstall them all using Pacifist, thanks for that link.

 

[SHADO]

Yea Pacifist is a must-have app in case anything happens to your apps, like what happened to you.