I'm getting very annoyed here. I think of myself as somewhat as an advanced computer user, but i just cannot figure out what is going on. This is the problem:

When i restart my computer, and log on to an account, it loads for about 3 seconds, and just stops (when the taskbar items should be loading up). All i can do is open the task manager. I figured it was an explorer problem, so i end that, and start it again but to no avail.

Each time i wish to use my computer, i have to system restore it back to last weekend. Once i do this, i can log onto one account, but as soon as my family tries to log onto their account, that account freezes, and i have to go back to mine.

I've tried everything... virus scans by many publishers (nortan, mcafee, system trend (?)) anti-spyware scans (spybot search and destroy, microsoft anti-spyware), but my system is sqeeky clean. And yes, i have updated all my definitions countless times.

Some help here would be great

It sounds like a corrupt user profile. Do this for each user on the computer http://support.microsoft.com/?kbid=811151

sorry.. i guess i didn't clarify.

The system logs on ok for whatever user that logs on first, after the system restore. After that, the other accounts don't work.

So every account actually works... as long as it's first

You mightt post a Hijack This log to see if we can spot the problem. You can download Hijack This at this link http://www.tomcoyote.org/hjt/ then place it into a folder of it's on, such as C:\HJT, so that back up copies can be made and not clutter your desktop or other folders and the backup copies of deleted items can be easily located if needed.

Once saved double click HijackThis.exe, and press "Scan". When the scan is finished, the "Scan" button will change into a "Save Log" button.
Press that, save the log, Ctrl-A to Select All, and copy its contents into the text editor to post the log.