I have a Samsung Galaxy S I9000, it keeps lagging; freezing and turning on and off by itself. I want to reset it, if I do will I lose all my photos, contacts etc etc..? I can't figure out how to transfer everything on to my SD card.
If you do a factory reset, your SD card will not be touched. Your pics, etc will all stay put. If you've selected your Google account as the default way to store your contacts, they will all repopulated from Google after you set up your phone.
If you want to be sure you're saving settings, etc. download Titanium Backup from the Google Playstore and do a full backup. After you've reset your phone, reinstall Ti and then do a restore from back up. Super simple!
Resetting your phone to factory settings will clear all the data on your phone memory, that is your contacts, calendars, applications downloaded from android market. Factory resetting can be done in settings (Navigation: Settings -> Privacy Settings -> Factory data reset)
Data backup can be done in settings (Navigation: Settings -> Privacy Settings -> Backup my data). Backup data can be restored after resetting. Certain applications give the option of data backup, if you have installed any apps from market, check for the option. Data backup can also be done using the software CD provided with the phone.
Your photos, audio mp3s, and videos will USUALLY reside in SD card and will NOT be erased. But its better you take out the memory card, and then go ahead resetting.
There are few ways you can reset your Android phone without losing anything. Backup most your stuff on your SD card, and synchronize your phone with a Gmail account so you won't lose any contacts. If you don't want to do that, there's an app called My Backup Pro that can do the same job. You can read more about how to ensure you don't lose any important information with a factory reset here.
There's an app My Backup Pro which you could use. From the description it allows you to:
Backup (with schedule option) to our online secure servers, or SD card, your Applications, Photos, Music, Videos, Contacts, Call log, Browser Bookmarks, SMS (text messages), MMS (message attachments), Calendar, System Settings, Home Screens (including shortcut positions), Alarms, Dictionary, Music Playlists, APNs, and more...
You can read more about it here.